Paul Bearer -- the spooky WWE manager who helped introduce The Undertaker -- died Tuesday evening at the age of 58 ... this according to the WWE.
Bearer -- real name "Bill" Moody -- joined the WWE in 1990 ... playing the role of a creepy funeral director who managed various wrestling stars ... including Undertaker, Kane, Rick Rude, Vader and Mankind.
The details surrounding Bearer's death are unclear -- but he reportedly suffered from serious health problems over the past decade ... including morbid obesity and gallbladder issues.
The WWE released a statement saying ... "WWE is saddened to learn of the passing of William Moody, aka Paul Bearer."
"Moody made his WWE debut in 1991 as the manager of The Undertaker and went on to become a memorable part of WWE over the course of the next 20 years. Our deepest condolences go out to Moody’s family, friends and fans."