A keylogger is an example of

A keylogger secretly records every keystroke a user types and sends it to an attacker, which is the defining behaviour of spyware.

A Trojan disguises itself as legitimate software to trick a user into installing it, a delivery trick rather than keystroke capture.

A worm is self replicating malware that spreads across networks on its own without needing a host program.

A logic bomb is dormant code that triggers a harmful action only when a set condition or date is met.

A keylogger may be delivered by a Trojan, but its own function of spying on input places it under spyware.

Keyloggers exist as both software and small hardware plugs fitted between keyboard and computer.