Avacyn's Collar, the Symbol of Her Church (MB2 509)

Artifact — Equipment • Mana cost: {1}{W} • Mystery Booster 2 • Rare

Equipped creature can't attack, block, or transform, and its activated abilities can't be activated.
Shackle {3} ({3}: Attach to target creature you don't control. Shackle only as a sorcery.)

Illustrated by Olga Kharyton.