Or even a Ghost - dogs can sense these things, especially BC's

I am sure and hope she is ok. xx

Collies are also extremely susceptible to boredom if their minds are not fully occupied for much of the day, and likewise with physical stimulus.

I am not saying that this is the case with your dog, and it may be that your collie is given adequate exercise both mentally and physically - it just seems like a typical made up game that's all!!!

My brother has always had collies, and being the sort of chap who does two peaks in the Lakes before breakfast, and several more during the day .....his dogs were certainly never short of exercise. Still, one of them was obsessed with chasing "images" on patterned carpets. Give her an hour with nothing to do, and she made up her own rather bizarre entertainment.

Despite getting absolutely loads of exercise and stimulus mine used to get two balls out of his toy box, have one in his mouth and push the other one around the room with his front paw, nearly always pushing it under a piece of furniture and I was up and down like a yo yo retrieving it.

That is exactly why I adore Collies!!! Wonderful dogs. Yours clearly had all the stimulus that he needed, but was still up for inventing new games!