Risky Roulette

{r}: {t}; Roll a D20
1-10: Take 10 damage, your creatures become
1/1 frogs and lose all abilities until end of turn.
11-20: Deal 10 damage to any target, put three
+1/+1 counters on each creature you control. Creatures with +1/+1 counters gain trample
until your next end step.