Tozgol, Insatiable Scholar

Ravenous Learner — Whenever you draw a
card, put a +1/+1 counter on Tozgol, Insatiable Scholar

Remove a +1/+1 counter from Tozgol, Insatiable Scholar: Create an Eldrazi Scion
with "Sacrifice this permanent: Add {c} to your mana pool"