eerie, frightening, morbid, hair-raising
scary
Frighten
Frightening
eerie
scary or eerie
The void was very dark and scary.
Horrendous Love?
Creepy, scary, unnerving, spooky.
Horrible, scary, disgusting,ugly..
scary, horrifying and/or frightening
One close rhyme is the word "merry" (fun). Another possibility is the word "airy" (light, pleasant).
the kids entered the dingy, dark, and scary chamber