Creepy one lately. The boat had been laid up for a bit, and the owner had asked for an electronics 'health check'.
One item was the radar not working. No rotation from the antenna got us to look inside the dome first.
With the cover off you can see what looks like droppings in the base. A bit closer (the blue circled area) something has been born here!
Another cocoon just below the rotating joint and opto. Moving the antenna by hand broke it up a bit (arrowed).
Clearing it out the motor was then able to turn properly, and the radar came to life again. Don't know what it was that had been (or still was!) in there, or how it even got in...