Player died after changing his character

ok so here just a simple video

EDIT: ok so i made Humanoid spawn on dummy from server side and now my character just disapears

If your pressing something like a keybind then there might be a script thats causing that, or if its a delay script then you can count the seconds and find the script in order to fix it, this post might not help but it might do something.

Im changing character by server sided script like Player.Character = Dummy