Redwall fanfiction where an old reclusive mouse ends up finding a baby rat, but since she’s half blind, she mistakes it for a mouse and adopts it. The rat grows up under her care and rapidly fading eyesight into a rat. A rat rat. One with a wicked hunched back and teeth that could gnaw through rock, the kind of creature you would see crawling from a slimy ship’s hull. Her grandson is well aware of what he is, but doesn’t notify her.
The few woodlanders that know the mouse are constantly trying to convince her that her grandson is a rat, but the rat stands back with a straight face and allows his grandmother to plow them over in a river of senility, occasionally piping up in agreement at the proper moment and holding her shawl for her.
“Look. Merrill. This has gone on too long. Yore grandson isn’t a mouse. He’s huge, for pike’s sake. Have you consid–”
“Now you hold on a second. Huge? My grandson’s a hardy boy and I don’t skimp on feeding him his meals, thank you; a plump child is a happy one, and I don’t think you have the right to shame my son for being study, Skipper!”
“Marm. Marm, that’s not what I meant–”
“I feed you three times a day, don’t I, son? We always have a good spread on the table, and you never go hungry?”
“Yes, you do, grandma. I eat plenty. It’s healthy for a growing young one.”
“Marm, I’m not sayin—”
“You were a plump baby! And you too, Logalog! You two had cheeks as big as apples and a rudder thicker than my arm, and you were a rolling, giggly little shrewbabe. Matter of fact, Skipper, I’ve held your grandniece, and I know she’s not a light little trinket either, as she shouldn’t be. Children need to be fed.”
“Of course, grandma.”