cant animate a collider

I’m working in 2D. I have a player sprite which draws a sword during an animation. I’d like a collider (simple polygon?) to follow the sword. I’ve tried giving the player sprite a collider and animating that along with the sprite animation, but it only seems to follow the center of mass of the sprite animation, rather than swinging.
I’ve tried creating a new 2D object with its own collider and animating that, but the same problem persists.
How should I be approaching this?

Go to the sprite in your assets (project pane) and select it. In the inspector you can go to the sprite editor.
In the sprite editor you can move the pivot to the point where your sprite should turn around. Don’t forget to save in the sprite editor.

Does that solve it?