Hedron Fields of Agadeem is a common Plane — Zendikar card from March of the Machine Commander (MOC), collector number 146. Current market price: $0.30, TCGplayer market prices via Scryfall.
Creatures with power 7 or greater can't attack or block. Whenever chaos ensues, create a 7/7 colorless Eldrazi creature token with annihilator 1. (Whenever it attacks, defending player sacrifices a permanent of their choice.)