What is the heaviest non-legendary Pokemon?

Question

...That knows a weight based damaging moves like Heat Crash, Heavy Slam, etc.

Answer 1

As of Pokémon Scarlet and Violet, Copperajah is the heaviest Pokémon. Though it only has a weight of 650.0 kg (1433.0 lbs) normally, its hidden ability doubles this to 1300.0 kg (2866.0 lbs) in battle, which actually exceeds the weight of Celesteela and Cosmoem. Copperajah learns Heavy Slam upon evolution

If we're excluding abilities here, Mudsdale is the heaviest Pokémon that is not Legendary, Mythical, or an Ultra Beast at 920.0 kg (2028.3 lbs). It learns Heavy Slam through level-up.

Mega Metagross technically weighs more than Mudsdale at 942.9 kg (2078.7 lbs), though it only knows Heavy Slam in games where its mega are unusable.

Comments

Copperajah gets Heavy Slam as soon as it evolves, and if it has Heavy Metal then it exceeds the normal weight limit and goes to 1300kg.

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Huh, I genuinely had no idea that ability existed. Thanks for pointing that out!

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*Technically* ultra beasts aren't legendary, which would be a shoe-in for Celesteela, but it's a pretty ambiguous difference that most people include UBs when talking about legendaries, anyway.

Answer 2

Aggron with heavy metal. It can learn heavy slam and with heavy metal ability it is almost 1500 pounds. Heavy slam is also STAB.

Source: http://www.serebii.net/pokedex-xy/306.shtml