Helm of the Host is a mythic Legendary Artifact — Equipment card from The Brothers' War Retro Artifacts (BRR), collector number 19. Current market price: $9.15 (foil $18.80), TCGplayer market prices via Scryfall.
At the beginning of combat on your turn, create a token that's a copy of equipped creature, except the token isn't legendary. That token gains haste. Equip {5}