Killer Klown

Killer Klown can't block.
As long as Killer Klown is concealing a card, it
gets +1/+1.
Conceal (When this enters the battlefield, you may
exile a card from your hand face down. When this
leaves the battlefield, turn the exiled card face up. You
may cast it without paying its mana cost if it's a
nonland card with lesser mana value.)