Seth

Seth is a Human from the Unicron Trilogy continuity family.

Seth is really celebratory over the idea of getting out of there.

Seth is Sid's lanky little yes-man who hides behind his buddy's bulk when shouting insults. They love to bully total nerds, so living in Science City must be like Christmas for them.

Seth attends the same school as the crass-yet-good-natured Billy, his doppelganger.

Fiction

Dreamwave Armada comics

While Sid was occupied trying to kill squirrels with his Dennis the Menace-style slingshot, Seth noticed their arch enemies, nerds, trying to have a good time. As Rad, Carlos and Alexis took off in their spectacular splendiferous balloon-mobile, Sid and Seth saw it as the perfect opportunity to send those three poindexters to an early grave. Using his slingshot, Sid popped the balloons keeping the contraption afloat. As the nerdlingers (well, actually just a dummy) plummeted to their deaths, Sid made a mean-spirited quip while Seth encouraged him to make a break for it, lest the law catch onto their gruesome shenanigans.

Little did they know, their homicidal plot didn't actually kill the paste-eating dorks, but helped them to become best friends with a team of awesome super powered robots from outer space. Take that, you little sociopaths! Dreamwave Armada #3