In an Gen 8 AG battle, I used Thunder Wave on the opponent's Dusk Mane, and it didn't Paralyze once! What is the chance of this happening?

Pokémon that are Paralyzed have a 25% chance of not moving that turn. So, we simply do (1/4)^12 (for the number of turns) and we get 1/16777216. Source: https://m.bulbapedia.bulbagarden.net/wiki/Paralysis_(status_condition)

I'm pretty sure it's something like 0.000000000001/1200, either that or 0.000000000001/1200 That's insane. Source:I just did the math on my calculator with the accuracy of Thunder Wave with my calculator.