Helios Duo Megistus

Level 6 LIGHT/Pyro Effect Monster
-1 ATK / -1 DEF

You can Special Summon this card by Tributing 1 "Helios - The Primordial Sun". This card's ATK and DEF are equal to the number of removed from play monsters x 200. If this card is destroyed by battle and sent to the Graveyard, Special Summon it during the End Phase, and it gains 300 ATK and DEF.

Rulings – Yugipedia

Printings:

Yu-Gi-Oh! Ultimate Masters: World Championship Tournament 2006 promotional cards: WC6-EN003 (Super Rare) - 2006-03-14
Champion Pack: Game Six: CP06-EN010 (Rare) - 2008-05-12
Speed Duel GX: Duelists of Shadows: SGX3-ENI22 (Common) - 2023-03-30

Prices:

Cardmarket: 0.10 €
TCGplayer: $ 0.21