A Killer Among Us (MKM 167)

Enchantment • Mana cost: {4}{G} • Murders at Karlov Manor • Uncommon

When this enchantment enters, create a 1/1 white Human creature token, a 1/1 blue Merfolk creature token, and a 1/1 red Goblin creature token. Then secretly choose Human, Merfolk, or Goblin.
Sacrifice this enchantment, Reveal the creature type you chose: If target attacking creature token is the chosen type, put three +1/+1 counters on it and it gains deathtouch until end of turn.

Illustrated by Leesha Hannigan.