Why don't Seismic Toss and Night Shade do supereffective damage against anything?

Question

Blissey used Seismic Toss, but Arboliva didn't take superrefective damage.

Answer 1

Seismic Toss and Night Shade do fixed damage equivalent to the user's level. There is no way for this damage to vary in battle, so there's no need to have an effectiveness message pop up.

Comments

I think it's worth mentioning that despite the fixed damage, these moves are still affected by the type chart when factoring in immunities, which is probably what could lead someone to get confused.