10 Worst Non-Signature Abilities In Pokémon Games
1. Truant
I know what you're thinking - "Truant is the signature ability of Slakoth and Slaking!" Well, it used to be, yes.
Truant, which holds the distinction of being the worst ability in the franchise (yes, worse than Slow Start and Defeatist), is also a hidden ability for Durant. This is a creative reference to the fact that ants work nonstop until they die and that they would only have an opportunity to "loaf around" in their dreams.
Aside from that singular shining instance of inventiveness associated with Truant, everything about it is dreadful.
Truant makes it so a Pokémon will do nothing every other turn no matter what. It will not be replaced by Simple Beam, Worry Seed, nor Entrainment - this ability is here to stay unless the Pokémon is lucky enough to face off with a Yamask or a Cofagrigus, in which case it will adopt the ability Mummy after hitting it with a physical attack. But again, this is a very specific and somewhat unlikely circumstance.
Truant is a sinful ability; an invitation for an opponent to build up their stats or land free hits. It sucks competitively, and it sucks in-game. Just save yourself the frustration - use a different Normal-type Pokémon or a Durant with Swarm. Avoid Truant at all costs. You'll be much happier that way.