Mana Sludge

Mutate 1 (If this creature would untap during your untap step, you may instead put a +1/+1 counter on
it)
Sacrifice Mana Sludge: For each +1/+1 counter
on Mana Sludge, add {b}, {r} or {g} to your mana pool.
It seeps along the jungle floor, absorbing excess energies so that they can be repurposed.