Ayara's Oathsworn (MAT 195)

Creature — Human Knight • Mana cost: {1}{B} • March of the Machine: The Aftermath • Rare

Menace
Whenever this creature deals combat damage to a player, if it has fewer than four +1/+1 counters on it, put a +1/+1 counter on it. Then if it has exactly four +1/+1 counters on it, search your library for a card, put it into your hand, then shuffle.

Illustrated by Chris Seaman.