Kog'maw and Zyra need new passives.

Death passives aren't always bad; they work well on Sion and Karthus, because their kit and builds encourage them to get right in the middle of fights, and their passives make them a continued threat even after they're brought down.

That said, what in the world was the design plan for koggles and Zyra getting death passives? It's legitimately nonsensical. If you are playing the champion correctly, you will never use their passive. That's terrible game design. A passive skill should meaningfully change how you play, just as much as QWER. I don't even care about the passives also being hilariously underpowered, they could do double damage and it'd still be poor design.

They need to be changed to something useful to the champions. Like, i don't know, maybe Zyra could take less damage from slowed/snared enemies. Koggles could recover some HP and mana when he kills a unit with a melee-range auto attack. I particularly like that because it helps his mana issues, but not without significant risk, and it fits his theme of eating (not puking, like all his other abilities :P)

Just spitballing here, literally anything but their current passives would be an improvement.