something makes a strange noise

[quarague]

what does the message in the title mean? I've seen it a few times, usually I loose somewhere between 5 and 10 hitpoints. I casted detection spells but I still have no idea what causes this?

[Therem Harth]

Not sure what spell that is, but it's being cast by something invisible. You need some means of See/Detect Invisible so you can clobber it.

[Derakon]

"Makes a strange noise" is the default sound for a spell that has no other associated message to use when you can't see the caster.