Jak had initially thought Sig meeting his fuckbuddy-slash-Metal Head ringleader would be a bad idea because they'd kill each other. Metal Head, Metal Head hunter, and so on. Now-- Jak shuddered, letting out a shaky moan as the Metal Head's dick jabbed deeper inside his fucked-open cock, Sig's hands wrapped around his dick, squeezing his massive balls, to give the Metal Head the leverage to thrust more roughly inside him-- now, Jak had a different idea of why it was a bad idea. Because they'd _team up_.

He was sprawled out across a canvas-draped stack of pallets in a docks warehouse, stripped naked, skin pallid with Dark Eco, cock a burning, bruised wreck between his thighs. The Metal Head was on top of him, sloppily drooling across his face between messy kisses, his cock stabbed halfway down inside Jak's brutalized cock. Everywhere else on him, as Dark Jak, was pale and pallid, skin an unearthly white. His dick was flushed a ruddy grey-black, black veins standing out starkly from his flesh, and his cockhead itself, warped obscenely around the gnarled, flanged Metal Head cock pumping into it, was a rich purple-black, with his bloated cocklips, each bruised as fat as a finger, so flushed they were solid black. A messy slurry of fluid spurting out of his dick with each thrust: his own backed-up pre, filmy grey, mixing together with the oily, gasoline-slick cloudy black mess that was Metal Head pre.

Sig was pressed against his side, his own hard dick rutting against Jak's hip as he messily joined the kiss, groaning deep into Jak's mouth as the Metal Head lapped across both their faces. Sig, he'd said, didn't have anything personal against Metal Heads. They just kept trying to kill everybody in Haven, if Jak had tamed one -- that was the exact words he'd used, even as the Metal Head had snapped and snarled, clearly not happy with that -- then he had no problem with it.

The fact that it had ended up saving his life from a giant Metalpede down in the Haven underworks had probably helped a lot too. Jak had thought the both of them had been dead, and when they'd slammed into the Hip Hog after everything: one battered Sig in dented armor, one giant Metal Head bleeding ichor all over the floor, well. One thing had lead to another pretty quick in his enthusiasm to see them both alive, and Jak had spent most of the night after the victory party on his hands and knees in Sig's dingy apartment, spitroast between the two of them. They'd bonded.

That had been a few months ago. Things had gotten a little more extreme since then.

It was one thing for Sig to sloppily fist out half-crystallized globs of dark eco from his swollen, inflamed prostate. But they'd both gotten a little too interested in seeing what his body could take. Flush with dark eco, no bullet would so much as bruise him, no blade could tear his skin, no fang could puncture him. He'd gotten hid directly in the chest with a rocket-propelled grenade once and all it had done was knock him over. It was maybe natural to test just how durable he was. Jak sure as hell didn't mind.

The Metal Head's giant reptilian paws tore huge rents in the oilcloth as it braced against him. Its cock flexed. The scalloped flare of its cockhead lurched, embedded halfway inside Jak's brutalized prostate, and his lean stomach visibly swelled, showing the gristled half-crescent clear through his taut skin as he arched back, howling and snarling, his own claws slicing through the oilcloth and straight through the wood pallet beneath.

Things pulsed inside him, inner passages burning and sore, hot cords of pain winding up through his hips, fanning out. He was clogged with a mix of his frothy pre; his own pent-up loads, silty and gritty; and a fresh wash of the Metal Head's oily, greasy pre. Ooze loudly slurped inside him, spilling out from his prostate, working backwards to flood his inner passages with sloppy, liquid froth. The Metal Head pounded forward, half-flared cock smashing into his prostate, warping the dense, mazy flesh outward around its cockhead, stretching it across its flare like a rubberband. Jak panted, keening, and Sig stroked his sides appreciatively, one hand reaching out to palm against the Metal Head's flare, stroking it through his body.

The Metal Head crooned, thrusts becoming harder -- yanking Jak's body back and forth, cockhead twisting and pulling at Jak's burning, fucked-open prostate -- until with an unearthly yowl it came, flare snapping wide, cock erupting in a sharp, burning squirt of Metal Head cum straight into Jak's passages: flooding them with a sloppy gurgle, forcing his already-inflated prostate to warp itself fatter and heavier, every fold blasted open under the scouring force of its sloppy, heavy spray. Jak sobbed, writhing beneath them, his own cock weakly flexing, his load gurgling inside him, stewing in his bruised, bloated passages to mix together with the Metal Head's load and form a thick, sloppy mess of slurried fluids. The Metal Head fucked him through its orgasm: shaft flexing hard, alien balls pumping, until a spray of their mingled slime squirted out around its shaft, gushing from Jak's cock in a mess. Metallic, quicksilver-looking cum, threaded through with clots and chunks, thick grit of half-congealed dark eco forming a pudding-like mass, gummy and thick, burbling out suspended in Metal Head cum.

When the Metal Head finally spent itself and yanked back, it left Jak's cock even more of a wreck: inner passages stretched and gaping, bruised from the scrape of its gristled flare, more and more slop just oozing out of him in slimy gushes. His cock was a fucked-open sheath, gaped cockslit slack and open, the rumpled flesh of his bloated cocklips soft and puffy when Sig easily shoved three fingers inside him, just twisting his hand around to drag his fingers along the inner walls of Jak's wrecked dick. Jak groaned, arching into the touch: the pressure of Sig's touch soothing some of the raw burn of getting fucked, even as the added stretch made the bloated, bruised flesh of his dick burn hotter.

Sig just snorted down at him, amused, as he reached deeper: four fingers, then his thumb, slurping over Jak's warped cocklips, until he had his entire hand sunk wrist-deep inside Jak's cock. He pumped shallowly, a mess of silvery Metal Head cum squelching out around his wrist and drooling down his forearm. He used his other hand to smear it across his skin, slicking himself up as he reached deeper: fingers scrabbling across his inner walls, feeling the lumps and gnarls of his well-fucked passageway, until with a burning _spang_ that made Jak yowl and arch his back, Sig's fingers popped through into his swollen, puffy prostate. Jak sobbed, black tears streaking down his face, hips reflexively fucking himself on Sig's forearm, as Sig probed across the folds of his prostate, blunt fingertips tugging and twisting at the delicate flesh: peeling apart gummed-together petals, spreading him further, teasing out messy squirts of slime from where they'd been trapped in his mazy passages.

The Metal Head kissed him, slavering tongue shoved down his throat to swallow his needy whines, its still-hard cock drooling the dregs of its load all across his bare stomach.

Sig's fingers caught against the first egg. Well, not _egg_. Metal Head gem. The Metal Head equivalent to an unfertilized egg. These ones were small and oblong: about a finger wide, half a finger in length, smooth and rounded. He groped through Jak's prostate, tugging and twisting to get the egg to squirt out into his palm, and then he pulled back, fist pulling free drenched in goopy slime, a single glimmering-gold gem caught between his fingers. Sig took a moment to kiss the Metal Head, groaning into its mouth as it slobbered across his face. Jak's cock -- Jak's empty, gaping sheath -- lurched and sluggishly collapsed in on itself. The broad oval of his fisted-open cock, framed by a stiff ridge of bruised flesh, seamed closed, ooze webbing between his inner walls as they met with a squelch.

Then Sig sunk his hand back into Jak's dick, fisting him open again.

Jak wasn't sure if it was just the dark eco powers, or all the Metal-Head-tainted dark eco he'd been marinating in since coming to the future. Realistically, getting fucked by Metal Heads had to have been part of it. Hell, Sig fisting dark eco crystals into his dick probably did some shit too. But regardless, _something_ had happened. His balls ached, packed full of tiny, bubbly Metal Head eggs, soaking up the dark eco inside him, growing fatter and heavier until he needed to have them milked out of him.

Sig's other hand was curled around the fat, hanging mound of his balls, fingers digging in hard to feel each lump and gnarl of his altered flesh. With a dizzying pang of pain, Jak felt eggs loosen inside him: lurching out from the dense folds that cocooned them in his balls, sluggishly siphoned up through the mazy folds of tubes filling his sac. Sig's fingers followed this egg all the way: pinching and squeezing it through his stretched passages, tugging and twisting his tubes through his sac to force it up and up, until with a sharp _spang_ Sig shoved his fat, blunt fingers against the root of his sac, popping the egg up into his inner canals. Jak writhed, gasping, sweat shining across his naked body.

It was internal spasms that carried the egg further, in a burning arc, until Sig could feel for it through his prostate. His fingers followed it for the final arc up, already probing at the end of the tight passageway it was travelling down, fingertips shoving inside in burning pangs. Sig sunk two fingers inside, stretching him brutally, and the egg squirted out between them, smacking into the vee of his spread fingers for him to curl around and haul back.

Two down. Sig squeezed one ball, and then the other, fingers and palm palpating it, putting enough twist on it to make all his inner passages slide against each other, forcing out a dense, tarry wash of his thick, altered sperm -- and with it, a dozen aching, burning spangs as half-formed gems slurped out of place, carried on a thick upwelling of sludge to clog his inner passages.

"Got a heavy clutch this time," Sig said, milking his sac with a slime-slathered hand, fingers digging into each lumpy gnarl. "Y' think any of 'em are gonna get fertilized? They keep getting bigger."

The Metal Head crooned in interest, cock gushing a fresh spray of oily black pre all up Jak's front. Metal Head cum helped his body push out the eggs; helped get them unstuck from growing fat and enormous in his balls. The natural conclusion -- maybe -- was his body got triggered to... _ovulate_, or something, from the Metal Head cum. From getting bred, or something like that. Metal Heads were the only other dark-eco-dominant life form on the planet, aside from Jak. Who knew how that was going to work.

But, with Sig forearm-deep inside his dick, Jak's misshapen sac a mess of bulging eggs squirming against each other, the Metal Head slavering across his face, well-- they weren't gonna stop experimenting until they figured it out.