bad fairy(n = noun.person) - a fairy that tends to cause harm;
is a kind of evil spirit

N  demon, daemon, demonry, demonology, evil genius, fiend, familiar, daeva, devil, bad spirit, unclean spirit, cacodemon, incubus, Eblis, shaitan, succubus, succuba, Frankenstein's monster, Titan, Shedim, Mephistopheles, Asmodeus, Moloch, Belial, Ahriman, fury, harpy, Friar Rush, vampire, ghoul, afreet, barghest, Loki, ogre, ogress, gnome, gin, jinn, imp, deev, lamia, bogie, bogeyman, bogle, nis, kobold, flibbertigibbet, fairy, brownie, pixy, elf, dwarf, urchin, Puck, Robin Goodfellow, leprechaun, Cluricaune, troll, dwerger, sprite, ouphe, bad fairy, nix, nixie, pigwidgeon, will-o'-the wisp, ghost, revenant, specter, apparition, spirit, shade, shadow, vision, hobglobin, goblin, orc, wraith, spook, boggart, banshee, loup-garou, lemures, evil eye, merman, mermaid, merfolk, siren, satyr, faun, manito, manitou, manitu, possession, demonic possession, diabolic possession, insanity, Maxwell's demon, demoniac, demonic, demonical, impish, demoniacal, fiendish, fiend-like, supernatural, weird, uncanny, unearthly, spectral, ghostly, ghost-like, elfin, elvin, elfish, elflike, haunted, pokerish, possessed, possessed by a devil, possessed by a demon, demonically.

bad, bad block, bad blood, bad boy, bad breath, bad character, bad check, bad cheque, bad condition, bad debt, bad egg, bad faith, bad guy, bad habit, bad hat, bad influence, bad job, bad lands, bad language, bad lot, bad luck, bad manners, bad name, bad news, bad notices, bad person, bad press, bad taste, bad temper, bad weather, fairy, fairy armadillo, fairy bell, fairy bluebird, fairy circle, fairy cup, fairy godmother, fairy lantern, fairy light, fairy ring, fairy shrimp, fairy story, fairy swallow, fairy tale, go bad, golden fairy lantern, in a bad way, not bad, too bad, tooth fairy, white fairy lantern