To dream of a ghoul represents negative attitudes or belief systems that feel good or benefit from hindering others. Mean, ignorant, or unsavory people that don’t think for themselves. Your view of someone who actively works to stamp out all that is good to your face. You view of someone who you feel is empty or soulless. An aspect of yourself that feels good permanently keeping others away from happiness.
Alternatively, a ghoul in a dream may reflect powerful bitterness or jealousy that feels good keeping others permanently weak for as long as it can.
A ghoul in a dream may also represent a petty unforgiving adversary who gets power from making sure you don’t get to like yourself.
Example: A woman dreamed of seeing her father with a “ghoulish” face. In waking life she had experienced her father lose his mind shortly before he died. The “ghoulish” face may have reflected her feelings about how intentionally cruel life seemed to degrade her father’s intelligence and personality so badly before he died.