Made a dark brotherhood character into a companion(mainly just a follow and stay) and removed most of his other movement functions he would do normally, but after a few moments a large thin but long box showed up out of his body, im pretty sure it might be because hes doing things he wasnt intended, but ive used other mods where lines and other bugs showed up for me, just curious what its all about or if its fixable. Thanks says the noob. XD

That's usually caused by using mod-added armor/clothing made for a different skeleton.nif than the one you have, and/or using the skeletonbeast.nif on races that don't have tails. Unrelated to your mod, unless you made a race edit that did it.