Xanathar's Eyeball

Xanathar's Eyeball enters with X eye counters
on it where X is the number of creatures you control. At the beginning of your upkeep, put
an eye counter on Xanathar's Eyeball.
When there are 10 eye counters on Xanathar's Eyeball, it transforms into Xanathar, The All Seeing Eye.