What are some words and sentences i could use to make a scary poem for english class?

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!