Just a video link with Mr. Dreamtree explaining the process of adding lyrics to music for "thE bEans". Backmasking is common and is generally regarded as "illegal" or "immoral".

thE bEans is my most bizarre music project. When I was a teen, my stepmother had a phonograph that allowed me to listen to music backwards and at high/low speeds, often revealing "Satanic" messages

Backmasking is a thing that is most commonly seen in the music industry. Here with Mark, we see that all of that is scripted and done precisely. There is no chance that these messages can occur randomly.

More music played backwards with disturbing messages

Dutch artist Jeroen Offerman practiced 3 months in a row to learn to sing Led Zeppelins most famous song entirely backwards. The Stairway at St.Paul’s” is based on the hysteria that surrounded certain