'Pokemon Go' Raid Guide: How To Beat Therian Forme Thundurus - Weakness And Counters The Thundurus in Therian Forme in Pokemon GO Photo: Niantic KEY POINTS The new Thundurus uses Poison instead of Ghost-type attacks Glaceon and Rampardos are effective against this boss while remaining relatively easy to get The Therian Forme of the legendary Thundurus Pokemon is now available to fight in “Pokemon Go,” but this raid boss is everything a raid boss should be and is strong enough to give any unprepared trainer a proper walloping. This new Forme has a few key differences from the previous Incarnate Forme. The Therian Forme has a new Poison-type move, and it sacrifices defense for offense, making it hurt more at the cost of being squishier than before.