there are pins you can put on a tie. usually just a gold button or something point symmetrical. like this: DDG link, but pointing to pinterest

but i think it is quite funny, that this person 'aims' the gun at their own head...

That could be a tie pin. They're to pin the tie to your shirt so that it doesn't fly away on the wind or something.

It's a tie tack, that's a normal thing. But it being a gun is tacky as all getout.

Hey..you could get shot in the neck with a gun there.