Answer:
Made from animal skins, monkey balls and humans who where extremely sick( mostly the elderly). They where killed then cute up into small pieces and stuffed into jars for two years. When they're cute up body parts where to that point where it was falling apart they took them out used special machines to flat out the skin's. After they where dried out they attached it to the shell of the drum. Then putting the otter metal ring around the hoop and screwing it to the drum, and that's what the top of the bass drum is made of.