The Baku is a gigantic sea serpent which inhabits a community of Mer people on an unknown ice planet. It inhabits the deep-sea realm under a thick layer of polar ice, surviving by mind-controlling it's prey around it to feed themselves to the "Baku garden": the resting place of the manipulative worm. When Hunk and Lance become stranded in the undersea kingdom, they help to free the populous of it's control by killing the Baku.
The Baku is a giant worm-like creature with a wrinkly white underbelly, and an orange hide covered in swaying green vegitation. It doesn't appear to have any facial features: instead, it's face opens up and separates into four jaws, like the petals of a massive purple flower. Each jaw has a row of small teeth, with a secondary ring of teeth located at the top of it's oesophagus. It has one long pelvic fin which runs the length of it's belly, as well as two wing-like dorsal fins which flare in response to an attack.
The Baku sources food by mind-controlling it's prey. On it's back, it produces vast amounts of edible marone greenery. When consumed, the greenery enebales the Baku to psychically control the eater, didcting their movements and speech. The Baku expands it's influnce by commanding prey to convince their peers to eat the mind-controlling vegitation. In this way, the Baku can convert an entire host of beings so that they are ready to be eaten at any time, avoiding the energy-consuming hunting or scavenging process undergone by other predators.
Once the Baku had the majority of the Mer population enthralled, it allowed their complex society to continue normally so that unsuspecting outsiders could be lured in and join it's collection of mindless soon-to-be-meals. The phrase "safe and warm" is regularly repeated by Queen Luxia as a mechanism or trigger phrase to maintain control. One of the riled imposed upon Mer society was that treason - disobeying the Queen - was punishable by entering the "Baku garden"; never to be seen again. The "Baku garden" was really the Baku laying dormant, surrounded by vegitation, and it continued to slowly deplete the Mer population this way before Lance and Hunk intervened.
When the Baku is discovered to be the source of the mass mind-control, rather than the previously suspected Queen Luxia, Hunk and Lance fire on the worm and it awakens. The Baku fights by swimming at great speed, strangling it's opponets and biting them with it's four mouths. It shows a resistance to being encased in ice, but vulnerability to the Blue Lion's sonic canon and being crushed by a rockfall.
- The Baku's control leads people to believe they are somewhere "safe and warm".
- It is not known where the name "Baku" originates.
- The Baku species has only been seen once, and it is not known if more of it exist.