Why are the legs falling through the plane?

I have a Player made of multiple objects (everything being the children of the “body” object). When I run the game, the legs fall through the plane until the body is on the ground, preventing the object from falling further. I have already tried adding rigid-bodies and collides to the legs to no avail.

The legs fall because they don’t have collides, they can’t collide with the plane.
You can add collides to the legs, and don’t add rigid bodies.