It's Maxwell, the three legged cat of Adam Ellis aka Adamtots, the cartoonist who drew this and many other awesome comic strips. He also has a black cat called Pepper. Their instagram is super cute.
Cartoonist: @adamtots
Cats: @maxwellandpepper
You should check them out
Cartoonist: @adamtots
Cats: @maxwellandpepper
You should check them out