We'd been talking about a Borderlands AU for Tam and Frank for a while, but nothing much really became of it 'til I decided I wanted to draw Tam in BL2 style, and I happened across concept art for the rats and it showed one without the gas mask on and they're,,, rlly cute oh no

And because they've got those big noses I thought "I wonder what Frank would look like if he were one..." and uh, there you have it

Also, admittedly, I completely forgot about the fact rats in Borderlands (2) wear gasmasks, but I found out they're like... symbols of status and also worn all ritualistic-like, so maybe he's just a social reject among other rats, which kind of works out 'cause Tam ends up picking him up and bringing him along her travels, sooooooo.....???