sparkplug blown out, came apart the treads are still in the head. How do I get it out ?

The lower part of the spark plug with the threads also has the 5/8" hex head for the spark plug socket. I've never seen or heard of anyone being able to twist the metal portion of the spark plug apart. Find a mechanic before you end up needing a new cylinder head or used motor!

If you can jam anything into the section of spark plug left in there to see whether it will screw out easily it may screw out. If it wont then likely it is a job for a mechanic.

Chip the ceramic electrode out so you can use an EZ-out reverse bite removal tool. Use a micro vacuum to clean out the cylinder.

If the aluminum head threads are jacked up, you will need a shop that can install a helical fix (typical issue on many Ford engines).

It does make one wonder why ford only has 3-5 threads in the plug wells, and why they continued to sell engines with bad heads.

Edit to add; Not only Ford Triton truck engines, it's also common on boxer engines and overheated air cooled engine jug plugs.

Your mechanic can do it. There's a tool for that.

Get an easy out at the hardware store. It is a reverse drill bit. You need a drill that will run in reverse.

If it is a Ford Triton engine, take it to somebody who has dealt with it before. All the methods that involve the usual ways of removing a broken plug are likely to damage the head.

If you have to drill it out use an anticlockwise drill piece to reduce the shavings going into the cylinder, use a magnet inside the cylinder to collect any swarf/shavings and spray a lot of WD40 In there before putting a new plug in and starting it, the wd40 will help get the swarf out of the engine without damaging anything while it runs

Usually when a spark plug blows out, it's just the ceramic core that comes out of the metal case. You SHOULD still be able to remove the case with a standard spark plug socket wrench.

That sucks, I had one break off like that years ago due to super heating in the cylinder from the turbo. Melted the threads partially to the head, plug broke off while I was trying to torque it out. There are multiple tools to try to remove it. Autozone, etc sell spark plug extractors and extractor kits. Another tool called an Easy-Out can be found at auto parts, hardware stores, etc, and is basically a tool that you drill/torque into the busted end of a broken plug/bolt/pin and then back out the original broken part. I think the threads go reverse on the Easy-out, or something like that.

F-150? You get the vehicle towed to a mechanic with a special tool to remove the part in the head.