Ruling Applying Damage Correctly

[Rufi0]

My question is regarding the wording "Prevent all effects of attacks, including damage..."

I've seen this wording on other cards, but have included Sigilyph with Safeguard for the sake of example.

Does this prevent any and all damage, or only additional damage done due to the effect of an attack?

For example, if an attack reads "20+ Flip 2 coins, this attack 20 more damage for each heads." Does Sigilyph receive the base damage of twenty and then negate the additional coinflips, or does it receive no damage at all?

 

[PMJ]

It receives no damage at all. Increasing the base damage of an attack is still damage done, which Safeguard explicitly blocks.

Flipping coins or discarding Energy in order to increase an attack's base damage is also not counted as an "effect of an attack"; rather, that's still configuring the base damage of the attack. So if you are preventing all effects of an attack, but not damage, the damage will still go through, but if you are preventing all damage, then you do.

 

[Rufi0]

Would Mewtwo-EX's Damage Change be able to affect a Pokémon with Safeguard or a Pokémon with an attack effect such as Jolteon-EX's Flash Ray?

 

[jessalakasam]

Would Mewtwo-EX's Damage Change be able to affect a Pokémon with Safeguard or a Pokémon with an attack effect such as Jolteon-EX's Flash Ray?

Mewtwo would heal itself only in the safeguard situation, in the Jolteon it isn't doing damage it's moving counters so the attack would play out normally

 

[My Little Keldeo]

As jessalakasam said, Mewtwo-EX's Damage Change would work normally if an opposing Jolteon-EX had used Flash Ray. Flay Ray only prevents damage, not other effects of attacks.

In the case of Safeguard, or Regice AOR's similarly worded Resistance Blizzard, which prevent all effects of attacks, things work differently. Only the effects done to those Pokemon by Damage Change would be prevented. Mewtwo-EX would remove all of its damage counters, but instead of being transferred to the protected Pokemon, they would be discarded. Any damage on the Safeguard Pokemon would also not be changed.