Terran Scientist: Why yes it has, Sir. It seems they are no longer a threat. Something new has come along though.
Terran Commander: Oh really? Do tell.
Terran Scientist: It's a rather large, rotund squid-like being, which seems to have been slightly flattened.
Terran Commander: Goodness! It sounds ferocious! How dangerous is it, Stephenson? Describe its weaponry.
Terran Scientist: Well, Sir, it spits green blobs of what is presumably acid.
Terran Commander: Egad! Surely that can't be all? There must be more to it, or the Zerg would have continued to use their Kamikaze fighters!
Terran Scientist: Well yes Sir, it seems they have the capability to be sick all over our spaceships too.
Terran Commander: And how damaging is this vomit?
Terran Scientist: Well, not at all actually. However it does seem to weaken the armor on our ships. After about half a minute it all drips off though.
Terran Commander: Truly a fiersome foe!
TL;DR: A scientist thinks the Corruptor is rather bland.