Viral Spawning (Phyrexia: All Will Be One 194) - Uncommon Magic: The Gathering Card

Create a 3/3 green Phyrexian Beast creature token with toxic 1. (Players dealt combat damage by it also get a poison counter.)
Corrupted — As long as an opponent has three or more poison counters and this card is in your graveyard, it has flashback . (You may cast this card from your graveyard for its flashback cost. Then exile it.)