The Stake

{r/w}{r/w}: Attach this permanent to target creature
an opponent controls with mana value 6 or less.
Activate this ability only any time you could cast
a sorcery.
At the beginning of your upkeep put a Stake
counter on attached creature. When a creature
has 2 or more stake counters on it, its controller
sacrifices it.
attached creature can't attack or block.