Persistent Undeath

Flashback {7}{b}{b}
Choose one:
•Each creature has Persist. (When this creature
dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner’s control with a -1/-1
counter on it.)
•Each creature has Undying. (When this creature
dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1
counter on it.)