Killbot #4

Killbot #4 is exactly what the name promises: a numbered unit in some Futurama war machine, one voice among a line of interchangeable killing devices. It exists to follow orders, mouth off in formation, and be indistinguishable from Killbots #1 through #3 except for whatever single joke the script hangs on it.

The gag is the flatness — a character defined entirely by a number is funny precisely because Futurama treats it with total seriousness, giving it lines as if it mattered. Billy West, doing what he does best, finds a specific comic voice for a nothing role, proving the joke works better the less the character is.