Ronnie Bergstedt is a scout boy and is in Ms. Vanthrax's classroom and a close friend of Ginger. He has curly brown hair and wears glasses. In "Cheat Code", he reveals that he is Builder X, an elite SquareStack player.
Ronnie is an eccentric, geeky kid with large, round-rimmed glasses and a scout uniform that he wears everywhere.
Besides the time when he stole Ginger's science fair project, he is seen to be quite nice to the friends, being friends with Ginger in particular.
Still, he is quite wimpy, often cracking under pressure and shying away from danger. For example, during a father-son beanbag contest, he hid in a barrel while his father fought for him.
- Talent Show: He was a contestant at the singing contest. He scored 29.5 points out of 30.
- The Lost Scouts: He was one of the scouts at a scout trip.
- The Substitute Teacher: He was one of Ginger's classmates.
- Tom the Brave: He was at the dentist appointment. When Tom came back hypnotized, Ronnie allowed him to go before him.
- The Other Tom (non-speaking)
- Cheat Code: It was revealed that Ronnie was Builder X. He gave Tom a cheat code for SquareStack, which Ben modified and broke the game.
- Retro Sonic Angela (non-speaking cameo in flashback)
- Glitch Apocalypse (non-speaking cameo in flashback)
- The Secret Life of Ms. Vanthrax (non-speaking)
- The Bad Germ (non-speaking)
- The Weather Machine (non-speaking)
- Basketball Hero: He was in Hank's class.
- Escape: Impossible! (flashback, cameo)
- Ginger and the Girl: He was made the partner of Darren for the science fair. They were having trouble coming up with ideas, so while Ginger explained his idea, Darren filmed his explanation. Later, when Darren fell victim to Ginger's "lie detector gum," he admitted that he stole the idea. He presumably received a zero on the assignment for plagiarism.
- Dude Ranch Showdown: He attended the school field trip to the Dude Ranch. He revealed his father and participated in the bean bag contest, but was defeated by Ginger.
- Prank Attack!: He was a part of the Prank Day song at the beginning and unintentionally messed up the rhyme of the song.
- The Incredible Super-Fan (cameo)
- Everybody Hates Tom (cameo)