Blug, the Wizened

Whenever a creature you control enters or leaves
the battlefield, put a brew counter on Blug, the
Wizened.
{r}, {t}: Remove all brew counters from Blug. It
deals that much damage to any target.
{g}, {t}: Remove all brew counters from Blug.
Add that much mana to your mana pool in any
combination of {r} or {g}.