Which type of virus or destructive software could appear to be useful but will actually cause damage once installed or run by a user?

A Trojan horse appears useful but causes damage once a user installs or runs it.

A hoax is a false warning or message, not software that damages a system.

A worm is self-replicating malware that spreads without disguising itself as useful.

A system sector is a region of a disk, not a type of destructive software.

A Trojan relies on tricking the user rather than spreading on its own.

Trojans often carry a hidden payload such as spyware.