Flayer King, Dragrimoth

This spell costs {1} less to cast for every blue and
black creature you control
Indestructible, Hexproof
Grand Corruption-{x}{u}{b} This creature gets X
+1/+0 counters until the end of this turn, then
take control of X target creatures opponents
control until the end of this turn, those creatures
gain Haste and are untapped