Icathian Surprise - Kog'Maw's Passive

I have a habit of suggesting champion ideas as stories, so give me a sec.

Cho'Gath grumbled and moaned as he made his way to the Rift. He hadn't been summoned in a while and his stomach was making noises that were scaring the minions that were wandering around waiting to spawn. Not having the chance to nibble on a minion or five, or even the odd champion always gave Cho'Gath digestion problems. Thankfully, he spotted Kog'Maw eating from a bucket of something or other.

"Fellow Voidling, good to see you, what is that you're eating?"

Kog'Maw clawed the bucket closer to himself. "Is special food. You in match today?"

Cho'Gath nodded, but his mind was on his empty stomach. "And your match is after, yes?"

"Yes."

His stomach made a loud rumble, and Cho'Gath covered it with one claw, feeling slightly embarrassed. "I'm sorry, I haven't eaten in a while. May I have some of your food?"

"Um, no." That was rather blunt of Kog'Maw. He was normally quite keen on sharing. "Is special. Only for me."

The Terror of the Void growled. "But I saw Karthus take a couple of those strange tablets you're eating..."

Kog'Maw hesitated, still keeping the bucket of weird-looking food close. But he knew that Cho'Gath could and would just snatch the bucket if he refused again. With even more hesitation, he gave a third of the bucket's contents to Cho'Gath, before quickly waddling away.

After eating and arriving on the Rift for his match, Cho'Gath felt much better. Maybe that was Kog'Maw's good luck meal or something, because the match was going great. He'd nommed his way up to all six stacks and he'd managed to chase off the enemy jungler with a well-placed series of spikes to the face. But there was a team fight coming up.

Knowing what was about to happen, Cho'Gath charged in, his team right behind him. While his spikes had knocked half the team up, he missed the marksman, who was firing away at him. A brief ultimate later and Cho'Gath was dead. Or was he? he was still standing among the enemy team.

Worse than that, he felt rather bloated and purple.

Suddenly, Cho'Gath exploded.

"PENTAKILL!"

But yeah, this is basically a silly suggestion of giving Cho'Gath the passive of Kog'Maw, because it makes no sense on Kog'Maw. He's a marksman, he's not supposed to be 'rewarded' for dying and he's rarely in the middle of combat, normally skirting the edges of it.

Cho'Gath on the other hand, being a huge tank mage thing, is often in the middle of combat.

I don't know about numbers though, the initial damage ought to be lowered, but it scales based on your level. The range of the explosion would increase based on your stacks, but damage would decrease based on how close you were to Cho'Gath at the time. In order to keep Cho'Gath's sustain though, maybe the health and mana on kill bit could be added to his E?

As a final suggestion, could Kog'Maw have an alternate animation for killing minions in melee range, where, instead of spitting at the minion, he eats them? The poor Voidling always complains he's hungry but he never eats anything!