Rakdos, The Thrill Killer

Thrill-Kill (If you have destroyed 2 or more creatures, creatures you control have "{1}{b/r}{b/r}{t} sacrifice this creature; destroy 2 creatures with converted mana cost less than or equal to the number of creatures you have destroyed
Creatures you control have deathtouch, flying and "when you destroy a creature put a +1+1 counter on it"