Curse-Rotted Greatwood

Curse-Rotted Greatwood enters the battlefield
tapped with three slumber counters on it.
(As long as it has a slumber counter, it is not
a creature)
Whenever a player attacks you or a planeswalker
you control, you may pay {1}. If you do, remove
a slumber counter from Greatwood.
{t}: Add {b} or {g}