Solid

Solid is a behavior that that determines whether the actor can overlap with other actors during a collision.

Solid is typically used for the collisions of Dynamic actors. If actors with Fixed Movement and/or No Movement collides with each other, it will not work and they will only move through each other. Only Dynamic actors cannot move through Solid actors. (unless it gets squeezed, then it might flew off)

For more information, see Collision.