Demon Summoner

Lifelink
When Demon Summoner enters the battlefield,
you may scry X, then reveal the top card of your
library. If that card is a creature with power equal
to or less than X, put it on to the battlefield with
a summon counter on it.
Demon Summoner's gets +X/+0, where X is the
greatest power among creatures with summon
counters you control.