Arnie is a professional electrician who was hired by Dexter's Mom to fix the house's wiring, but due to a mysterious wire, he ends up in Dexter's Laboratory. Seeing the poor state the lab is in, Arnie decides to fix it thus improving it's capabilities by 100%.
Arnie is an obese male who works for an unnamed electric company. He wears an orange button shirt with a collar, jeans, and brown shoes. He has black hair, a black mustache, and black sideburns.
- When viewed from the front, Arnie's mustache resembles the mustache seen on the video game character Super Mario.