Abyss

{t} Two target creatures gain X -1/1 or X 1/-1
counters. If target creature's toughness is reduced
to zero due to this effect, it does not die and is
instead exiled at the end of the owner's turn.
For every turn that Abyss is in play, create a X/X +1 Humanity token.
Exile Abyss after X + X turns.