Marnie, Bringer of Gifts

Marnie, Bringer of Gifts enters the battlefield with X gift counters.
Marnie gets +1/+1 for each gift counter on it.
Whenever a Dog you control dies, if it did
not have a -1/-1 counter on it, you may
remove a gift counter from Marnie. Return
it to the battlefield with a -1/-1 counter on it.