Susan is Tom's electric bass guitar. It was first seen in Ruined. She is easily Tom's most prized possession, as he is very protective of her. She makes recurring appearances in episodes. In the later episodes she appeared in, she had bandages on her neck because of what took place in Ruined. She appears to be a Fender Precision Bass with a Fender Stratocaster pickguard. Interestingly, in real life, Tom's bass is actually a Music Man Stingray 4.
- Ruined: Tom had gotten a new bass guitar and left it in his room. Edd peeked in his room and saw it, so he picked it up and played with it. When a spider crawled near him, he used Susan to squash the spider, breaking Susan's neck in the process. He ended up digging a hole in the backyard to hide Susan from Tom, discovering the underground Egyptian tomb in the process. Tom discovers Susan in the yard as the boys examine the tomb door, horrified at her damaged condition. In the later episodes she appeared in, Tom's tie is on Susan's neck.
- 25ft under the seat: Although she does not appear onscreen, Edd apologizes to Tom for breaking Susan as the boys are sentenced to death by oxygen by the Atlantisians (only to survive as they breathe oxygen).
- WTFuture: Tom had put Susan in a special safe to protect her. An eye scan was required to open it. Tom took Susan along with him when they were running from Future Edd. Later on, Edd took Susan out of Tom's hoodie and whacked Future Edd with it. Tom and his future counterpart ran to Susan and started mourning over her. They ended getting crushed by a lamppost afterward.
- Zanta Claws 3: Tom and Zanta had a guitar battle in the sleigh. Tom was playing Susan while Zanta played an electric guitar, she may have been destroyed when Edd, Matt and Santa fired a missile at the sleigh.
- The End: Tom can be seen fixing a broken Susan in his new apartment at the end of Part 2.