Kill Bear or Kirugumar (きるぐまー Kirugumā?, Yen Press: Killerkuma) is a mascot found in merchandise in the ToAru Majutsu No Index universe, although, it is not as pervasively present as Gekota. Misaka Mikoto is a fan of the character.
https://toarumajutsunoindex.fandom.com/wiki/Kill_Bear