Momotarou

Being the sole surviving wartime experimentation specimen to manufacture an esper animal, Momotarō is Kyōsuke's squirrel companion that sometimes behaves quite cluelessly as to Kyōsuke's modus operandi as he adds his commentary to whatever Kyōsuke does or is deciding. Momotarou's strongly- and frequently-demonstrated affinity for sunflower seeds one night causes him to be sucked into the slipstream of a passing truck and electrocuted by live power lines for no other reason than his obdurate refusal to let go of the seeds. If pushed into combat, Momotarou has the capability to compress the air around him into acoustic concussion missiles that he launches at his adversaries as well as an intense but transient siren that scrambles and encrypts the brain waves of anybody in the vicinity. When Kaoru tries to nurse him back to health, Momotarou has psychotic episodes as he recalls all the experimentation he has undergone that cause him to lash out to tremendous effect but fortunately sees that Kaoru and her teammates are kindred spirits even if he has not yet resolved his hatred for humans as a whole.
(Source: Wikipedia)