Arcana Force XV - The Fiend (MZMI-EN015) [Maze of Millennia]

You can discard this card; add 1 "Light Barrier" from your Deck or GY to your hand. If this card is Summoned: Toss a coin and this card gains the appropriate effect.
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• Heads: When an attack is declared involving this card: You can target 1 monster on the field; destroy it, and if you do, inflict 500 damage to its controller.
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• Tails: When an attack is declared involving this card: Destroy all monsters on the field.