A person who is ardently devoted to a particular subject or activity
Afflicted with or exhibiting irrationality and mental unsoundness
If this other maniac Bryce could find us, so can he.
You could've popped that maniac before he dragged you over the cliff.
In that light, his reaction to her appeared less like that of a moody homicidal maniac and more like one of a jilted lover.
Another famous mare was Manganese (1853) by Birdcatcher from Moonbeam by Tomboy from Lunatic by the Prime Minister from Maniac by Shuttle.