It lower stalker stealth making them easier to spot. It's also work pretty good vs melee toons if you fight in/around tar patch they don't have much of a choice but to play in it.
@Intro lolPvP
Bad Melee's perhaps, Smart ones will Kite through it. Jumping around and timing attacks so that when the animation goes off they land outside of it.
Would tar patch help me not get AS'ed?