Every Star Trek Reference In Futurama
26. Evil Beards In The Lesser Of Two Evils
The Lesser of Two Evils introduces Flexo. Flexo is another bending robot, like Bender. Leela assumes Flexo is evil and blames him when a valuable package goes missing. This is because Flexo has a goatee.
While the goatee is somewhat universal in media to show someone evil, it is clearly a reference here to mirror universe Spock. In the episode Mirror, Mirror, a transporter malfunction swaps Kirk, McCoy, Scotty and Uhura with their counterparts in the mirror universe. The mirror universe is one that is far darker than the prime universe. In it, The Federation has been replaced by The Terran Empire and they are far more bloodthirsty and violent. In the mirror universe, they meet Mirror Spock who is notable for sporting a goatee.
The goatee that mirror Spock wears is a real goatee as opposed to flexo's cartoonish triangle beard, but the reference is there to the evil Terran empire and the twins that the crewmembers of the Enterprise have there.
Flexo is actually less evil than Bender and often jokes around, being friendly with members of the planet express crew. This subverts the set up with the goatee as mirror Bender, instead creating a fun and charismatic character.