Bun Bun Symbiote is an enemy that appears in Into the Future: Chapter 3.
The Alien variant of Teacher Bun Bun has very high health and very high attack power. He is a bit harder to defeat than the other Bun Bun variants, due to him having half as many knockbacks. Even worse, he has a 5% chance to create a Level 1 Shockwave. Luckily, the shockwave comes out rarely; in other words, Bun Bun Symbiote doesn't make a shockwave most of the time.
While the shockwave is rare, it can destroy your meatshields and long-range attackers due to Bun Bun Symbiote's high attack power.
Even though he can only create a Level 1 Shockwave, this still greatly increases his range, killing all of your Dragon, Ururun, and Bahamut units and knocking back any Ubers that you may have.
Bring as many anti-floating/anti-alien freezing units as you can, like Castaway Cat, Delinquent Cat, or Akira. This can help lessen the chance of a shockwave occurring. It helps to also bring powerful alien/floating resistant units like Sodom and Mekako Saionji. (Normal form/True Form only for the latter). These units can withstand hits from shockwaves.