Synonym for an evil object?

Solution 1:

obscenity

The bullet is nothing but an obscenity.

This is a word an anguished relative or friend of the innocent victim might use as she/he rails against the immediate cause of the victim's death.

According to Dictionary.com, an obscenity is something that is obscene.

The Free Dictionary has as one of its definitions of obscene

abominable; disgusting; repulsive

Scourge - Oxford Dictionary

A person or thing that causes great trouble or suffering.

I also have heard Cancer used in this way. Merriam-Webster

Something bad or dangerous that causes other bad things to happen

I also agree with Bane but it was suggested already!