Teresa is a Genderswap/R63 Trollge named "Summer Trollge". She has 2 different selves "Summer Teresa" or "Sunset Teresa"

Sunset Teresa has no known appearance due because Summer Teresa doesn't want her alter ego to hurt anyone. She's a parallel version of Summer Trollge of course.

An upcoming character for Undertale The Souls Incident Summer DLC. By Jmccormic / Jmcchannel

gallery:

"Hey i wanna to her"

This is how Teresa actually looks like without the "meaty" body parts to troll her simps. Teresa's real body is also similar to a stickman like her male version (with circles instead of boobs), that is this leathery body is just a cover to attract attention and then subsequent trolling lmao (basically figures) so ye this is her true form (the gallery is part of her Shapeshifting)