Testicleese is named after the make-believe Roman god of Virility. In-game he is an avatar of a Guardian, a large, grey, round monster. This gives the appearance of a large grey testicle.
In-game, players affectionately refer to him as Testy.
Testicleese is the alternate player of Admin Grant, a beloved long-time admin of the game known for his compassion and even-handedness.