Heraldic Beast Basilisk

[Regarding the effect "After damage calculation, when this card battles an opponent's monster: Destroy that opponent's monster"]

This is a Trigger Effect that activates in the Monster Zone.

It activates automatically exactly once after damage calculation when this card battles an opponent's monster. (It also activates if this card is destroyed by that battle.)

This effect does not target.

This effect activates even if the opponent's monster that battled this card is already determined to be destroyed by battle. (In that case, the opponent's monster is destroyed by the effect, and is not treated as being destroyed by battle.)