Is creeped a metaphor?

No, crept (this is the way you write this word, not 'creeped') is a past tense verb. A metaphor is when you compare two objects (nouns) by saying that an object is something else. For example, 'he had arms of steel' is a metaphor because a person's arms are not actually made out of steel. A verb is an 'action' word which shows that something is happening.