Suggestion for Singed: Poison Trail becomes an "Immolation" effect while Singed is ulting

One problem Singed has is that he has to get ahead of his target to hit them with Poison Trail, as no one these days is stupid enough to chase him unless he's already dead. In team fights, this basically makes Poison Trail really ineffective.

I'd like to suggest that while Singed is using Insanity Potion, Poison Trail should turn into a kind of "immolation" effect. It'd still leave a trail, but Singed would also surround himself with a poisonous cloud, poisoning any enemies he gets too close to.