[[Bailey Briggs]] is a 10 year old kid who was removed from the 616 timeline. The Home Dimension of the Marvel Universe. 
He is not to be confused with the Spider-boy from the amalgamation universe which was combination of the DC and Marvel Universe heroes. Notably Superboy and Spider-man. 

What we know about Briggs so far is that: He's been Spider-boy for 3 years, according to him. Meaning he started when he was 7. Dan Slott clarified on twitter, the creator of Spider-boy, that means that Briggs started around the Spider-man event called "Big Time"!

His powers seem to be similar to Peter's in that he has superior strength and the ability to stick to walls. Except that his Spider Sense seems to warn him of upcoming peril. Leading him on as he likes to call them, "Side-Quests"!

He also seems to begrudgingly use the word, Side-kick when referring to him and Spider-man's relationship. 

We don't yet know why he was removed from the 616 timeline, but given Spider-man's reaction to Briggs being Spider-boy in the current 616 timeline and that he hadn't [b]earned[/b] his webshooters yet from the previous 616 timeline (according to Briggs). It's more then likely Peter might have altered the previous 616 timeline by removing Briggs from it, thinking he was saving the kid from a life of super heroics rather then dooming him to be forgotten in the new current 616 timeline. 

Think Spider-man in No Way Home when he had Dr. Strange erase himself from people's memories in the MCU, if that helps.  
except it's way worse because Briggs no long has a mother, nor does anyone remember him personally along with his secret identity. 

* [[spider-man]]
spider-boy (spider-man)