>>54849449A shitmon is a Pokémon intentionally designed to be awful - available very early with low stats, often reaches its final evolution stage by Level 20, often has a powerful (Hidden) Ability that would be busted on a stronger Pokémon.
So something like Gumshoos which has 3 amazing Abilities and a good attack stat of 110, but most of its other stats are 60 and below so it doesn’t even have the bulk nor speed to capitalize on its potential power.
Bibarel would also fit as it evolves at Level 15 and its highest stat is an 85 in Attack, with every other stat being 50-79. Again it has 3 amazing Abilities but it lacks the raw power and speed to capitalize on Moody and Simple, and lacks the bulk to be an Unaware user.
Watchog has Analytic, but it isn’t deliberately slow (built for Trick Room slow) at 77 speed to make use of the Ability. It also lacks the bulk (60/69/69) and power (85/65) to be an Analytic mon. It doesn’t help that Watchog has both NP and SD and a great special movepool.
Corviknight and Crobat do not count. Corviknight was designed to be the mid late game bird over alternatives such as Cramorant. Crobat was designed to be a shitmon at first but becomes respectable due to evolving further in Gen 2 (and most Pokémon were shitmons in Gens 1 and 2 anyway). Silvally functions more as an Onix or Miltank sort of role where it has to be somewhat weak to not be too difficult as a boss, but impractical in competitive.
