Help with a custom projectile?

I’m working on a projectile that would be fired and embed itself into whatever it hits. The user should then be able to walk / jump on it as expected. Walking onto / jumping onto it works fine, however if you try to move while on top of it you get launched in a random direction. I can’t figure out what is causing this, I disabled motion on the object upon contact with a wall and that didn’t fix it.

Sounds like a physics issue, I would perhaps spawn a mesh in the same location of where the projectile hits and using that to replace the projectile. This should avoid the crazy physics issues.