It honestly depends on what type of poem you're writing and the topic.
If you're looking to creep out or scare the reader:
adjectives- awful, nasty, frightening, deathly, dark, evil, repulsive, unnerving
nouns- death, destruction, creature,
verbs- scream, run, kill, plunge, chase, pursue
emotions- fear, terror, anger, horror
Let me know if you're looking for something else!