Mouse Lynn is a small 4 inch tall mouse. She is a thief and takes contracts from clients to steal certain items from other parties. She uses a personal bag of holding to sneak large treasure she cant normally carry out of her heists. Once she stole a cursed artifact and while putting it in her bag she was afflicted with the curse. The curse was mean to cause her to transform into a large kaiju monster, but luckily the wizard she was stealing from stepped in and helped her before she destroyed his tower. (Apparently he wanted to get rid of the artifact anyway). The wizard marked Lynn with a glyph that kept her from transforming.

This glyph isnt perfect and the curse still affects her in various ways. There are 4 main instances.
-First her normal 4inch self.
-Second: When she gets stressed her size will shift to the size of the kaiju (400 feet tall).
-Third: When the glyph is weakened she will transform into a draconic mouse monster at her full 400 foot height but keep her mind unaltered (minus a few urges and impulses).
-Fourth: If the Glyph breaks or becomes inactive she will become the draconic mouse monster at her full height but her thoughts will be based purely on instinct and likely go on a rampage or accidentally cause damage she would otherwise be mindful to avoid.

She still keeps up with her career and the old wizard is now a good drinking buddy and returning client. However now there are instances of a giant mouse bursting out of buildings and running off without and clothes carrying a treasure chest or sometimes an entire section of building. Eye witness guards state they saw what they thought was a thief before getting knocked into the wall and knocked unconscious.
Instances of the glyph weakening are very few but there are legends of a draconic mouse beast that terrifies a town but causes no real damage.
Luckily the glyph has only broken once, and this happened in an abandoned ruin in an isolated place. She had walked into an antimagic field that disabled the glyph and it took about a week for the magic to recharge itself. She remembers her time feeling like a wild monster and really didnt like not having her wits about her.

Fun facts:
-She loves cheese, bread and meats - using her earnings to try all she can.
-She kinda likes the power rush from her monster form
-She once grew from stress during an nightmare and accidentally exposed the thieves guild hideout in a famous city when she burst through ceiling into a busy market street.
-She really doesn't like the fact that growing leaves her naked. She is constantly looking for a set of clothes that are enchanted to grow with her.
-The wizard knows how to make those clothes but doesnt and teases her as payback for initially trying to steal from him.
-The wizard did give her one item that grows with her a mask to keep her face hidden while on jobs.
-She uses two needles as swords. One sharpened and turned into an actual small sword, the other unaltered and used to parry and poke in a fencing style.

Art by the amazing  Shadowraiser

Help with backstory and inspiration from  kevlimeth and their cute mouse!