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 Dragons, Ururun, and Bahamut and possibly knocking back any Ubers that you may have.