Cats. The wife and I had to pull out the Cat whisperer pro tips in the last couple days. Our two cats, Pepper and Cinnamon had some kind of falling out while we were away for a day. Little Cinnamon was acting terrified of everything. Any little sudden sound or movement and she poofs up like a pufferfish. Pepper was acting all dominant and grumpy. But no tufts of fur, no injuries visible.
So we separated them into closed rooms. Laundered everything they lay on. Scrubbed out the cat boxes. Then carefully “reintroduced” them. All is well, apparently.