My Apple Pencil will only appear connected when stuck to my iPad pro

As described, your Apple Pencil is displaying symptoms of a dead battery - that will not accept or hold any charge.

The tiny internal Li-ion battery is susceptible to permanent/irreversible damage through being left discharged for long periods. Even some “new” pencils can exhibit signs of failure out-of-the-box if they are “old stock”.

It is essential that if you have an Apple Pencil that you charge it regularly - whether used or not - so as to protect the battery from deep-discharge. Do not allow a pencil to remain in low-charge state for any period of time - as the internal battery will fail, rendering the Pencil useless.

If the Pencil Battery has failed, the only remedy is to replace the Pencil. If purchased directly from Apple, if the battery has failed and your pencil is within its one-year warranty, you should look to having it replaced when the Apple Stores eventually reopen.

Here is one of the better fault-finding guides for Apple Pencil:

https://appletoolbox.com/apple-pencil-not-working-heres-our-troubleshooting-guide/

I hope this information proves to be helpful in both diagnosing and resolving the problem.

Sounds like the battery in your pencil is gone. Sounds like it isn’t taking a charge anymore and has to be replaced. Did you have the pencil off for a while and let the battery go dead and then wait a while to charge it again? Is this something that just started happening? If the pencil is less than a year old, you could get a hold of Apple and it should still be under warranty and they will most likely replace it. However, if it is over a year old, it’s going to need to be replaced and it won’t be covered.

Almost sounds like a bad battery

Prior to this issue, when was the last time your Apple Pencil was charged up and used?