For example, there are one or two flies in my house. I don't know where they came from, but it is February, and cold, so the flies are sluggish. Sluggish flies! (Now I'm imagining slugs with wings, so I have to pause for a brief memory wipe.)
OK, I'm better now.
Take dogs: dogs frequently wear sheepish expressions after doing something forbidden but overwhelmingly tempting, like eating the entire birthday cake in three gulps, candles and all, while mommy is off fetching the matches.
If you prefer (I do), take cats. My boy cat, now eleven years old, tries to ravish my girl cat, his sister, at least twice a day. His ravenous glare betrays his wolfish lust as he doggedly pursues poor Kitty Janeway all through the house. Since he has soft fleecy fur and a tendency to emit loud bleats when hungry I often call him a wolf in sheep's clothing. A cat-wolf in sheep's clothing, you see - and weren't there a dog and a raven in there as well?