Is it possible to squash/skew one side of a selected area instead of the entire thing?

[cgoose500]

https://imgur.com/a/dkP9qQY
Like this

[sam]

I don't think so :(
maybe go to the aseprite website and check the forums. You could maybe suggest it.

[behreajj]

Here are some links where a cage transform and/or perspective transform suggestion has been made:
Other types of transformation?[community.aseprite.org]
Cage Transform feature request[community.aseprite.org]
Free distort transformation[github.com]