7 Jun 2024
A creature that is equipped is considered modified no matter who controls the Equipment that's attached to it.
7 Jun 2024
If the creature you don't control is an illegal target as Signature Slam tries to resolve but the creature you control is a legal target, you'll still put a +1/+1 counter on the target creature you control.
7 Jun 2024
A creature with a counter on it is considered modified no matter what kind of counter it is or which player put it on that creature.
7 Jun 2024
An Aura controlled by another player does not cause a creature you control to be modified.
7 Jun 2024
If the creature you control is an illegal target as Signature Slam tries to resolve but the creature you don't control is still a legal target, each modified creature you control (which may include the target creature you control if it's still on the battlefield) will still deal damage equal to its power to the creature you don't control.