The Bandersnatch is a 0° stable color-changing glider reflector (also known as a "glider shifter") discovered by Entity Valkyrie on June 5, 2020 based on a reaction by Martin Grant. The repeat time is 70, slightly less than the syringes repeat time of 78. Since it contains an eater 2, an eater 1, a loaf and four blocks, it is Spartan. The name is taken from Lewis Carrolls The Hunting of the Snark.

The day of its discovery, Goldtiger997 used this reflector to reduce the repeat time of the highway robber. Later that day, Tanner Jacobi used it to reduce the size of the period-70 glider gun, and Adam P. Goucher discovered that the glider produced by the Bandersnatch could be fed into a nearby rectifier to produce an efficient merge circuit. On June 10, Sphenocorona constructed a p143 Bandersnatch loop using two Bandersnatches and two copies of 66P13. On January 3, 2022, iNoMed reduced this to create a bandersnatch loop supported entirely by relatively small still lifes.

Pattern of the Year for 2020.