The FrogNstein is an enemy that appears in Crash Twinsanity in the Academy of Evil. It's only seen in Classroom Chaos. It appears in Crash's section of Classroom Chaos in glass cases. It's seen later as an enemy in Cortex's section where they hop around certain classrooms. FrogNsteins can be seen in the Green Gem Gallery.
In one of the concept art galleries, it is seen when Cortex, N. Brio and N. Gin try to escape away from Madame Amberly, Cortex bringing Victor and Moritz and next to N. Brio there is a FrogNstein, which it seems that he created it (because they both have bolts in their heads) or just they encountered one, however it will remain as a mystery.