What’s up with people’s avatars only having 1 leg?

Am I missing something? Some Roblox characters seem to only have one leg and the other one is shriveled. I’m so confused like.. is this a trend? I’ve only been on Roblox since December 2024 and Google doesn’t seem to understand what I’m asking. I tried asking people and they all said idk. I’m also not sure if I picked the right tag for this topic so sorry if I messed up