All toasters toast BREAD. Trying to toast toast would proably result in rather burnt toast...
Not quite. For example, when someone "bakes bread" they're really baking dough, not bread.
That's a quirk of the word "bake." We are said to bake a cake. It is a conundrum.
One paints a picture, although they are really painting a canvas. It's transitivity with the direct object indicating the future finished product.
Additionally, while the bread is in the toaster, thee must be some point when it stops being bread and instead becomes toast. And unless you eject the toast precisely at this moment, then your toaster does indeed toast toast. This can be applied to all toasters. Therefore, all toasters toast toast.
How did Mario know Peach was in that castle in the clouds?