Bonnie is a blue animatronic rabbit that has magenta eyes and a red bow-tie. He has large teeth and a black nose and his teeth are rectangular. Like most of the other animatronics, he has four fingers and three toes.
In FNaF World
Bonnie and all his variants are playable characters in FNAF World. Most of them are unlockable, like Spring Bonnie and Springtrap, but he and Toy Bonnie are available to be used in the beginning of the game. Adventure Bonnie's main weapon is his guitar, which is used for two attacks.
Adventure Bonnie is a solid beginner character, and is arguably the best beginner character you start with.
Bonnie, similar to Freddy, plays the role of the attacker of the group, however he has some small but key differences which makes him more reliable than Freddy during the mid game. However he still gets outclassed by mid to late game characters as you progress through the game.
Bonnie has two attacks and one support ability. Bite and Bash Jam are both solid early game attacks. Bash Jam should be your go to attack while using Bonnie against multiple targets, it isn't as strong as Pizza Wheel in most cases however it is still very decent. Bite should only be used against single enemies or bosses, even if it does more damage then Bash Jam, it is always better to damage multiple enemies when there are more then one.
Bonnies' main draw over Freddy however is his Happy Jam ability, Bonnie is the only starting character that can both do reliable damage and also reliable healing during the early game. (Toy Freddy has Party Favors, however, Party Favors does little damage and little healing and is usually not worth using) He can even be considered a better healer then Chica as he is able to attack enemies when the party doesn't require healing, during the early game, extra damage is always welcome.
Bonnie, however, falls into the same category as most of the other starting characters in that all his abilities get outclassed by later game characters, during the mid-game with phantom characters and withered characters, Bonnie's damage output simply can't keep up. And it isn't worth having a character with 1 healing ability and nothing else being useful, especially when characters like Toy Chica have better support abilities like Birthday and Waterhose. His Bite and Bash Jam get outclassed by attacks such as Pizza Wheel 2, Eyebeam, Toxic Bite, Unscrew or Unscrew 2, Balloons, and Esc Key. While Happy Jam simply isn't worth using an entire character slot for when other support characters have more options.
In the mid-game, he should be replaced by any character with stronger multi attacks, such as Withered Bonnie, BB, JJ, or basically any animatronic with better Red or Orange colored attacks, or with another support character that has more support abilities like Toy Chica. In the late game, he becomes redundant as the Nightmare, Endo, and unique characters (such as Crying Child), outclass all starting characters in the game with abilities like Power Song, Armor Song, Neon Wall, Bite 2, Gifts Boxes, Mega Bite, Fredles, and Springlock.
Five Nights at Freddy's AR: Special Delivery