Firstborn owns a pair of plastic statues of transformers. They don't move, and they don't transform. Originally, they were toppers on a birthday cake. Firstborn also owns a great number of Imaginext toys, including several from their Outer Space setting. The little Imaginext space-guys have helmets that fit down over their heads and shoulders. One of these wound up in the shower, somehow, with the Transformer statues. So, in a fit of whimsy, I stuck it on Bumblebee's head.
This led to the following conversation:
Firstborn: "Why does Bumblebee have a mask?"
Me: "So nobody will know that he's a ninja."
Firstborn: "Bumblebee isn't a ninja."
Firstborn: "He's a Transformer. He's not a ninja."
Me: "Then why does he have a mask?"
Firstborn. "I do not know."