Frog Pond

Frog Pond enters the battlefield tapped.
{t}:Add {g} or {u}.
{t}:Create a 0/1 green blue tadpole creature token
with tadpole enters the battlefield with 3 time counters on it.
at the beginning of your upkeep, remove a time counter from tadpole.
If there are no time counters left on tadpole, sacrifice it and create
a 1/3 green blue frog creature token.