Celebrant, the Dragon King

Flying, Terrorize 2 (when a creature blocks a
creature with terrorize, it becomes tapped and gets X
stun counters)
Adamant Scales—Tap any number of untapped creatures you control with total power 4 or more: Celebrant gains indestructible or hexproof until
end of turn.
The immense dragon loomed head, neck, and
shoulders above the wall of the keep.