OK so its not a gadget, but this looks like a fun way to deal with flies and it is shaped like a delete button.

 DELETE
there’s no esc for flies!

This handy flyswatter works on windows or Macs…just think of
it as a backspace for bugs! Delete is molded from high-tech
plastic that’s flexible yet strong, and it hangs from the handy
bead-chain loop. Charcoal, Ivory, or Assorted. Peggable
recyclable clamshell packaging.

No word on pricing or availability.

Product Page via Nerd Approved