How do I keep objects with Rigidbody from moving slightly after they stopped?

I have prefabs that have Rigidbody2D, with Gravity: 0, Drag = 0, and Mass: 1.

I all shoot them in the same direction with constant velocity towards a collider, and they're supposed to pile up, without bouncing off.

• the 1st prefab hits the collider, doesn't bounce off, stops completely and is unmovable (exactly the way I want)

• the 2nd prefab hits the 1st prefab, stops, but bounces off very slightly and slowly.

• the 3rd prefab hits 2nd prefab, bounces off more

• the 4th prefab bounces off even more.

I tried to change the physics setting of the project but that didn't change anything. How do I get all prefabs to stop completely and be absolutely unmovable?

Thanks in advance