The idle animation not playing is on me.
equip.Stopped:Connect(function() --- This fires the code when the animation is done.
idle:Play() --- Removed the first 3 dashes here.
end)
Also for the sword to be on your back, you will have to place it prior to activating the tool.Activated function; You pretty much do what is within the weld creation. You’ll just have to call WeaponLocation() at the end of your script, provided that the tool is placed in the player’s backpack beforehand by adding this:
WeaponLocation()
to the end of your script!
Now the animation freezing problem is back.
Have you played the idle animation by itself to see if it was the issue? My replications do not seem to have any issues.
No, I didn’t. I’ll check later since my sister’s laptop just died on me. 
Alright, I just checked. I believe that it’s the issue, which is odd.
The idle animation was perfectly fine before, I’ve never had this issue before.
Edit: While checking the script, I noticed that
handle.Parent = player
had player underlined, and it said this: “Unknown global ‘player’”.
I forgot to rearrange that line while testing; replace it with Character.
Did that, and now it shows on my back when I equip it and unequip it again. Looks like I’m basically running into the same problems over and over. The idle animation still is freezing in place.
Edit: Looks like when I reset, the idle animation frozen in place thing is gone. But no sword shows on my back after resetting so I’m assuming that there’s something in the script which causes it to show the sword on my back after I equip and unequip it.