Rotted Underbelly

Suspend 3 — {x}{x}{b} When you suspend this
spell, note the value of X.
When Rotted Underbelly enters the battlefield,
place one rot counter on it. Then if it was cast
from exile, place an additional amount of rot
counters on it equal to the number noted for X.
At the beginning of your upkeep, create a
number of 1/1 black Rat creature tokens equal to
the number of rot counters on this card.