Botwoon is a species of Maridian serpent that is located in the upper portions of Maridia in Super Metroid. It's a minibus and guards the location to Draygon. Even though it is not considered a Space Pirate you must defeat it to gain access to Draygon. Weather it's sapient or not is unknown though.
Botwoon makes it's first and to date only appearance in Super Metroid.
 Super Metroid
Located only in Super Metroid in the Space pirate dominated regions of upper Maridia, Botwoon must be killed to progress the game and access the Maridian boss Draygon. It's attacks basically consist of hiding in the holes in the background and shooting some kind of gooey substance, while its head is poking out of the wall, it can be shot with a Super Missile or Charge Beam attack.
When the boss has been damaged enough, it will collapse from the wall its hiding in and the various segments on its body will explode one at a time. The wall blocking the rest of the room will then explode and you will be free to progress to Draygon.
Botwoon doesn't hide any major power ups.
Concept art of Botwoon included in a German strategy has Botwoon (along with Draygon) located in the Wrecked Ship. While it is unknown wheater this guide is canon or not it is possible that the bosses could use the ship as a sort of hang out due to the proximity of the two locations.