Shout outs to Gen 1, where damaging Fighting moves couldn't hit them (all 4 or 5 of them), but Seismic Toss could because it ignored the normal damage formula and just did damage equal to your level. Night Shade was exactly the same but in reverse pretty much, as it was a Ghost move that did the same thing and could hit Normal Pokemon.

Gen 1 had so much wacky bullshit balancing that it really makes you realize it's a miracle the series became as big as a hit as it was. The game was very broken but that's what made it special.