"Corrupt" Status Effects (Status Effects with levels over 127) don't work on mobs like they should. They work on players, just not mobs. For example: Levitation 128 instantly sends me to the ground. However, for mobs, it sends them straight up. AFAIK this works with /effect, I haven't tested it with potion effects.
Steps to reproduce:
/summon Creeper
/effect @e[type=Creeper] levitation 1 128
Environment
Windows 7 Home Premium, Java Version 8 Update 45, "Intel(R) Core(TM) i5-4460S CPU @ 2.90GHz 2.90GHz" processor, 8.00GB RAM (7.88 GB usable), 64-bit Operating System
Those amplifiers aren't supported