| Billy Irresponsible|
Billy Irresponsible and Bobby Irresponsible are father and son. They are usually used in adventures in Happy Wheels, or to cheat in spikefalls.
Billy is the son of Bobby. Usually called Timmy or Justin Bieber, Billy is a shy, over-reacting kid. He is about 6-8 years old, but we can't figure it out yet.
Jack hates Billy, and Billy hates Jack.
As to the reason Jack & Bobby hate Billy, it was revealed in Happy Wheels part 86 that Billy shattered Bobby's dreams of becoming an astronaut by coming into his life before he was ready for a son. In addition to this, Bobby's wife, whom he "loved to bits", died during childbirth, giving Bobby yet another reason to resent Billy (who wasn't worth his mother's death).
Kerbal Space Program
In Kerbal Space Program, Jack renamed Bill Kerman as Billy Kerman.
Also, Billy was featured in Jack's Turbo Dismount Ep. 23 "SCREW YOU BILLY" video.
Billy was once again introduced temporarily as a male child Sim named Billy McBOSS in his play-through of The Sims 4 until he was later trapped between walls with his sim sister Abigail "Abby" McBOSS and taken away by the Services in the episode titled KILL THE KIDS! | The Sims 4 - Part 4.
- Whenever someone named Bill or Billy is even mentioned outside of Happy Wheels, Jack either renames them Billy if their name is Bill or just screams "SCREW YOU, BILLY!".
- In the fan-made game Jacksepticeye's 1 million subscribers youtube party massacre, all the YouTubers are disappeared and some zombies wanted to kill Jack and his friends. After Jack completed this level, he appeared cryaotic after the conversation with Cry, then Cleverbot Evie appeared which controls the whole room to kill Jack. After Jack completed this level, Billy, the final boss appeared, because Billy planned all. He wanted to kill Jack because he was tortured in Happy Wheels and Jack says "SCREW YOU, BILLY!". After this conversation, Billy turned into a monster, Jack beats him, and then all Jack's friends was saved!
- Billy is considered to be Jack's arch-nemesis.