You pick up the leather belt.
It's a dark brown, almost black if you catch it in the shadows, and its texture is bumpy and rough under your thumb. It's a solid enough length, you surmise, though you decide to keep it folded in half for more power. The buckle on the thing is shiny and gray, though it's rusting, and the rougher scratching of the rust makes you cringe when you brush your hand against it.
The stranger's still fending off that weird painting, so you hurry back up the stairs to help them.