create new world

This should work on both 1.13 and 1.14, and is not limited to ‘tamable’ mobs, either. So even if you have a pet squid or slime this will work on them!

If you’re playing singleplayer: start by going into the escape menu and clicking “Open to LAN”. Once you are in there, enable cheats, and then press open. Once that is done, run the command seen below via copy/paste.

If you’re playing multiplayer: you must the server admin or an op, then just run the following command by copy/paste.

/data modify entity @e[name=“<Pet Name>”,limit=1] Invulnerable set value 1

Obviously, replace “<Pet Name>” with whatever you have named them via a nametag. If it works, you will get the following message.

Now nothing can kill your pet!

Bonus: if you cannot find your pet, simply type:

/tp @e[name=“<Pet Name>”] <Your Username>

However, you must be close to where you lost them, because it won’t work if they are in an unloaded chunk.