As part of a complementary set we are doing based on Battle for Westvale(https://mtgcardsmith.com/user/ElMagici/sets/29269
), I came up with this ability, and I need some opinions.
Ability: Planelock (This creature can't change zones, if creature life is 0 or below, tap it, it doesn't untap during it's controller's untap step)
Story-wise, this ability represents the magical disruption of the plane caused by a misfired legendary spell destroying the Planar Overseer (https://mtgcardsmith.com/view/planar-overseer
), causing some creatures to not only being unable to die, but neither can be caged or vanished out the plane.
Mechanically speaking, this is a semi-nerfed-but-still-overpowered ability that prevents the creature to be exiled or destroyed by removals but at the same time, taking a hit can knock them out for two turns.