I was cleaning up a bit - read that as finally putting away the Christmas decorations - and I put a reindeer on the lounge in Rusty's spot (at least in his world it's his spot). At first he just looked at it and went away with a forlorn dog look (droopy ears, head down) but then he ventured back and decided to tackle the intruder. After a bit of wriggling and squirming Rusty was able to reclaim his spot even though the reindeer held out for a position perched on Rusty's back.