Gergar, Gladiator Goblin

Whenever Gergar, Gladiator Goblin becomes
blocked, flip a coin. If heads, Gergar gains a
Winstreak counter, and the creatures blocking
Gergar cannot deal combat damage this turn.
If tails, Gergar loses all Winstreak counters.
Gergar attacks an additional time for every
Winstreak counter. On 5 counters, he gains
+3/+3, Double Strike, and Trample. On 10
counters, count every coin flip as heads.