not followed by nobody (double negation) [duplicate]

Negative Concord

This "quirk" of speech is actually quite well-documented. It is called negative concord.

However, I agree with Your Dictionary:

Double negatives are generally discouraged in English because they are considered to be poor grammar and they can be confusing.

"A little party never killed nobody" just means "A little party never killed anybody."

To understand double-negatives, just get rid of either negative:

A little party ever killed nobody. (A little party killed nobody)

A little party never killed somebody.

However, the best practice is abandoning their usage because they are ungrammatical.