New Collar Day 2

What does Bob do to these?

The first collar we got him lasted a weekend and disappeared into the ether - no sign of it anywhere. This put poor Bob on house arrest till we could get out at this weekend to get him another. We dutifully did so and also put on the dangly magnetic thing for the flap (which he has still to master). We let him out tonight and after an awful guffaw from him and the next door cat he came scooting back into the house sans collar. A quick scoot out with my Maglite and I found it under some bushes in this state - it certainly didn't look like that in the shop!

So - what's he been up to?!