The Mercurian boomerang spoon were an unusual culinary utensil originating on Space Corps space stations on the planet Mercury. It operated on the same principle as a boomerang, retrieving food from a distance and bringing it back at rapid velocity.
One of the boys from the Dwarf, the Series 4000 Mechanoid Kryten, said that as part his cooking duties programming he was equipped to use many off-world techniques, mentioning that the boomerang spoon was the one which was most often lethal. Kryten brought this up to Legion as the gang were presented with a space feast aboard the Legion Station, although the boomerang spoon itself is perhaps wisely not presented.
Kryten was also programmed to use Mimosian Anti-Matter Chopsticks and Telekinetic Wine (which he is shown using), and also the "Jovian boogle hoops" (not seen). Everyone, even Kryten, struggled to use even the chopsticks. (Legion, Series VI)