Based on caterpillars, Boa-Boas are successors to the Caterkiller. They have purple and gray armor and a body consisting of nine segments, with the head on one end and a small tail on the other. Except for their head, all the Boa-Boas' body segments have hatches on both lateral sides that spit out flames.
|Sonic||Windy Valley, Icecap, Lost World|
In gameplay, Boa-Boas constantly glide gracefully through the air, spouting puffs of flame from their sides. In Sonic's chase, the player can attack a Boa-Boa from above or below using the Homing Attack when it is not spitting flames (doing so will damage Sonic). Hitting any segment on a Boa-Boa will blow the entire robot up. When playing as E-102 Gamma, the player can take advantage of the Boa-Boas; for each body segment the player locks onto and hits, they are granted a Time Bonus.
In Sonic Rivals, the Boa-Boa appears as a collectible card.
- The Boa-Boas' name may be allusion to boas, a family of non-venomous, constricting snakes.
- The appearance of the Boa-Boas seem to be mix of the Catakiller, Jr. and Fireworm.