Becquerel Harley, also known by his Pesterchum handle callingCujo, is one of the main characters in Guidestuck, as well as the first one introduced.
He was first shown on a large island, only accompanied by his dog, Jade. This is the first showcase of the alternate universe depicted in Guidestuck. While in Homestuck, one of the main characters, named Jade Harley, has a dog named Becquerel, in Guidestuck, Becquerel is the human and Jade is the dog. Because of this, Bec has white hair that sticks out on the sides, representing a wolf/dog.
Bec has spent most of his life on the island. When he was young, he had a guardian, referred to as a grandpa by Bec, named Halley, based on a dog of the same name from Homestuck, but Halley disappeared when Bec was young.
Bec used to play on a MMORPG when he was about eleven and was repeatedly defeated by Jaspers Lalonde. At the time, he had bad grammar, could not read and had few, even no friends. He could not understand what Jaspers - also eleven - had said to him and so kept playing and kept losing to Jaspers. He later on met a "new" person. It was Jaspers, but he had changed his online identity because he wanted to help Bec. Bec still has no idea that his past online bully and his best friend are the same person.
In the beginning of the comic, Becquerel is first shown with his dog, Jade, standing outside of his home and waiting for a certain package to arrive via airmail. Upon retrieving said package, he returns to his abode, described as an underground island mansion. Once there, the reader is shown Becquerel's room, as well as his interests.
Bec then immediately proceeds to open the package, which contains his Sburb Omega copy, and rips the discs. Once he has an electronic version, he intends to send it to Jaspers Lalonde, but is unable to, and the computer initiates the transfer itself. Jaspers and Bec then set up a connection, with Jaspers as the server and Bec as the client.
During the session, Jaspers, having virtually no control of the Sburb controls, accidentally kills Jade and then prototypes Bec's sprite with it, creating a sprite named Jadepuppysprite, or simply Jadepuppy. This is again a reference to Homestuck, where the dog Becquerel, as Jade was about to enter Sburb, prototyped itself.
- His name, as well as the name of Jade's dog Becquerel from Homestuck, comes from the name of the scientist Henri Becquerel, one of the discoverers of radioactivity.
- In the past, Bec and/or Halley also kept a dog named Jake. This again is a reference to the Homestuck character Jake English.