Character falls down on hit event-Removing physics

It’s going to be an mmorpg mob(enemy), so I want it to have no physics whatsoever. But it shouldn’t be static, it should be moveable. So here is what happens:
I used mixamo’s monster to test this. My main character has a laser skill, when it fires and hits the mob, the monster falls down on his back like this:

Also when I move onto the monster(i think it’s an overlap event), it again falls like a ball. I want this character to calculate no physics and give no response to hit and overlap events, but still be able to move(moveable selected on component properties). How can I achieve this?
I already tried no collision on both the root capsule and the character mesh.