Ian Elvina, Mosvil's old man

When Ian Elvina, Mosvil's old man enters the battlefield or attacks, roll a d20.
•1 | Sacrifice Ian Elvina, Mosvil's old man.
•2-19 | Deal X damage Z time to any target, where Z
is the number of creatures you control.
•20 | Deal X damage Z time to any target, where Z
is the number of creatures on the battlefield.

Ian Elvina, Mosvil's old man power is equal to
number of creatures you control.