I remember a thread with an expensive survival knife supplied with some spikes you screw into the cross guard to turn the knife into a grappling hook - anyone else remember that too?
Magentus
I think it was made by Buck, round about 1985 ish. They made two versions - same blade shape but one had a skeleton handle, the other had the hollow handle and crossguard that you could screw the spikes into. Allegedly designed to be an anchor or a grappling hook.
Stop press - the Buckmaster 184 (hollow handle) and the Buckmaster 185 (skeleton handle) are the models.
Cheers