BB8 is a fictional male in the Star Wars film series who was portrayed on screen by -. BB8 is the latest droid to join the other two (C-3PO and R2-D2) in the star Wars universe. The easiest way to describe him is to say a ball with a half-sphere on top. He is owned by Poe Dameron, the lead X-Wing pilot of the Rebel Alliance and he is Poe's X-Wing co-pilot. At the start of the Star Wars - The Force Awakens, BB8 is entrusted with part of a map that shows where Luke Skywalker might now be hiding after having left the Rebels. When Kylo Ren captured Poe and took him off Jakku, BB8 is left alone to fend for himself.
BB8 befriends Rey after Rey cuts him loose from a scavengers net and they become inseparable. Rey doesn't want a friend but when she's given the option of selling the droid for sixty credits, Rey declines the offer and keeps her new friend even though there are interested parties wanting the droid. It is reminiscent of the first film where Princess Leia hides plans of the Death Star inside R2-D2 however it is Poe Dameron instead who does that. BB8 stays with Rey right throughout the film apart from when Kylo Ren captures Rey and takes her to his Starkiller Base.
Although he doesn't have any hands like C-3PO, he is able to shoot grappling hooks with wires to pull himself to where he wants to go. He also has a small robot arm that he can use with a small blow torch to cut or show his appreciation.
In The Last Jedi, we see another similar droid, BB-9E. BB-93 is a black Astromech droid that is aligned with the First Order.