The Mask of a Greek Port City, apparently?
RD/KP01-JP034 ヴォロスの仮面 Volos no Kamen (Mask of Volos)
Level 5 EARTH Spellcaster-Type Effect Monster
Requirement: Activate by sending 1 card from your hand to the Graveyard.
Effect: Choose 1 face-up monster (Level 6 or lower) in your opponent’s field, its Original ATK becomes 1500 until the end of this turn.
It might be referencing this dude, too.