Therion Cross - 25th Anniversary Tin: Dueling Heroes Mega Pack (MP23)

When your opponent activates a monster effect, while you control a "Therion" monster: You can activate 1 of these effects;
• Negate that effect.
• Banish that monster.
If you have "Endless Engine Argyro System" in your GY at activation, you can activate both effects (at resolution, negate, then banish). You can only activate 1 "Therion Cross" per turn.