Neck Tangle is a common Sorcery card from Face the Hydra (TFTH), collector number 10. Current market price: $0.67, TCGplayer market prices via Scryfall.
If there are five or more Heads on the battlefield, tap two of them and they don't untap during the Hydra's next untap step. Otherwise, reveal the top card of the Hydra's library and the Hydra casts that card.