remember low kick? the mediocre fighting attack that could cause flinch
well now, it brings a whole new factor into the battle

go ahead, use your bazillion ton metagrosses and obese slaking
cuz any machamp with low kick is going to sweep them off of their feet

official nintendo move description
low kick
power -
accuracy100
pp 20
inflicts higher damage if your foe's weight is heavier

isnt that just interesting, of course i dont know an exact formula but it sounds like it could be a sinister achilles heel to some teams. Im also not sure if it means heavier than the pokemon using low kick or using heaviness relative to all pokemon

the bigger they are the harder they fall