I swallow the unwary, but have no mouth. I hold you fast, but have no hands. The more you struggle, the deeper you sink. What am I?

I jingle and jangle on the cowboy’s boot, I’m small and shiny and kind of cute.

I have a mouth but never speak, A body but no arms or feet. I hold treasures, secrets deep, And often go for a walk on a street.

An admittedly old school item, I'm dark as the night. My purpose is to leave a mark, which I can do with the thing that enables flight.

A house has it, but a garden doesn't. A pavilion is essentially only this, supported by poles. What word are we looking for?