The Big Bang Theory: 10 Best Characters Who Only Appeared In One Episode
1. The Shelbot
Episode: "The Cruciferous Vegetable Amplification" (Season 4, Episode 2)
Sheldon wants to live longer, much to the annoyance of anyone who has ever met him, and so he takes a bold step: to preserve his life, he decides to seclude himself in his room and interact with the world via a hi-tech robot. Sheldon calls it a 'Mobile Virtual Presence Device', but we'll refer to it as the Shelbot, for brevity's sake.
The Shelbot takes the weirdness of Sheldon and upgrades it - giving him internet capabilities and wheels. The results are brilliant. It also makes him him a lot more embarrassing and inconvenient to his friends, which is even funnier. Apple co-founder and technology pioneer Steve Wozniak appears in this episode, which could've warranted a spot on this list, but Sheldon's robot manages to overshadow even him. The Great Woz himself acknowledges how cool it is.
The Shelbot deserves to be ranked amongst the most memorable of TV comedy robots - somewhere between Vicki (Small Wonder) and Bender (Futurama). 'Nuff said.