My iMac won't stop trying to connect to an unknown bluetooth device (shows as Mac address)

Rebooted (should have done that before) and it's no longer there.

I've had some problems occasionally where the trackpad and keyboard would keep dropping out - I'd wondered if the BT in the iMac was failing but now wondering if it was this rogue device trying to connect.

What's odd is that it wasn't showing up in 'other devices' on my iPhone so it's only the Mac that was seeing it.

Yes, that's what I found. Odd eh?

I'm at home, in a house with a fair bit of metal in it so it's unlikely to be coming from outside and it's not like there's *that* many bluetooth devices around that are actively seeking connections.