Just some thoughts that have been sticking around my head for a while, can it cleanse off abilities like Nautilus ultimate (not the knock up), Thresh hook, Nidalees Haunted (Q/W), Lulu's pix from her E, Twitch passive stacks, Fizz W, etc.
UNIQUE ACTIVE: Removes all stuns, roots, taunts, fears, silences and slows on an allied champion and heals for 150 + (10% of the target's maximum health). (180 second cooldown.)
copy pasta, just read the tool tip, only the CC that is listed is cleansed. So debuffs and displacements are uneffected.
It's better to ask what it can't cleanse off, since that is a substantially shorter list and tells you everything you need to know.
If you want to check that out, try looking it up on the Wiki here: http://leagueoflegends.wikia.com/wiki/Mikael's_Crucible
