Yep, been there, done that. Donkey stowed away on the trip to town (he never normally leaves the house) and got himself lost.
Fortunately we had a spare (and then we paid a fortune on ebay to get a spare spare when #1 never turned up – apparently he’s ‘collectable’ so we think he was donkeynapped. The spares have to rotate to keep wear even. Just writing this brings home the nth degree of planning that has gone into it)
Just to keep up the pretence, we faked a call from the bus driver, I went out to ‘collect him’ sat round the corner in the car for 10 mins and then brought him home to be reunited.
It has latterly come out that there are in fact 2 donkeys (she doesn’t know that #1 didn’t come home), and she absolutely refuses to have the spare one so we keep him ‘just in case’. And rotate them, to keep wear even, just as before.
We often wonder what would happen if #2 and spare #2 were to ever meet. It would take the Doctor to unravel that.