A collab I did with  turner148. Lineart by me, colors by them.

Plenty of mutants are known to go through secondary mutations, often giving them new abilities, which was the case with Big Bertha. When she unexpectedly underwent mutation advancement, she gained the ability to turn her heavy blubbery body into a huge balloon! She's still trying to get the hang of moving around in this form and learning what she can do, of course, and for how she deflates... one can probably guess how it embarrassing she finds it when she does it in front of other people!

The idea for inflated Big Bertha was provided by  ElCid