Screechyphobia

Screechyphobia is the fear of being screeched by Four.
 * Everyone in BFB has this fear excluding Four himself.
 * it exists irl for real
 * In the show, a tape recorder plays the screech, but no one was scared, except Donut.
 * Four's screech itself is from Freesound (a sound database that anyone can upload and download), available under the Creative Commons Zero License. Here is the link to the uncut sound.
 * According to Cary, it is possible to build up a tolerance to Four's screech.
 * In real life, Four's screech must be louder than 120 decibels in order to cause damage.