Me and my pet

I love my pet,

at the gas station, we met,

eating up crumpets and cakes

he is almost never bad,

though he ate up my dad,

and polished off my mum for desert

I taught him to draw,

but on the papers he did gnaw,

and he swallowed the glasses of paints

He is made of blue jelly,

and has a blue belly...

hey, is that my sister in there?