The Screamer is a white bat-like creature with gray feet, wings, and antennae. It has a long tail with a gray tuft of fur at the end. The Screamer has an enormous mouth that can send out a shrilling scream so high pitched it can shatter eardrums. It is recorded as the highest pitched scream an animal can make. Not only can it stun a creature just by screaming, it can also deliver a fierce bite with its long fangs.

Warriors skilled in battling with instruments sometimes tame Screamers to use in battle. There were a few during the Great Saxophone War who had Screamers. Tamers of these creatures usually wear protective earmuffs that block the sound-waves from harming their ears.

The Screamer is deaf but the antennae on its head can be used to sense vibrations instead of sound. This way, it won't hurt itself with its own screams.