This article contains canon information corresponding to the Tales of Arcadia franchise. That means all information in this article is true and has appeared/been validated officialy on-screen.
An antramonstrum is a vaporous creature that acts essentially as a guard dog; shockingly fierce. Lying dormant in a cluster of purple crystal until disturbed, it viciously attacks intruders and apparently leaves no trace of any unfortunate enough to be enveloped in its foggy form. Stricklander utilized one to guard his office, and later to make Principal Levit "disappear" so he could take Levit's job. You cannot see the scene, but you can hear the screams of Principal Levit and the laughter of Stricklander.