Zek Hal, the Old Wood

Zek Hal, the Old Wood enters the battlefield
tapped.

Whenever you activate a ritual ability of a
permanent you control, put a time counter on
Zek Hal.

{t}: Add {r} or {g} to your mana pool.

{3}, {t}, Remove X time counters from Zek Hal:
Add X mana of {r} or {g} to your mana pool.