What it looks like:
You don't need your wife standing next to you screaming, "MOUSE! OH MY GOD KILL IT, KILL IT NOW" to tell you what that thing is. If you saw one scamper across your floor, you'd bring out the mousetrap. The next day, when you found the little sucker impaled on the wall of spikes that your tiny mousetrap catapult flung it into, you'd toss it in the trash without a second thought. Well if you love adorable things, or are a fan of the posters in elementary school libraries, we've got some bad news.
What it actually is: A tiny little mutant koala
Image By Quartl
The brown antechinus' lack of a placenta makes it a marsupial, which means that long before it looked, acted and pooped all over your boxes of old family photographs like a mouse, it descended from the evolutionary great grandfather of the koala. Once they split up, the antechinus developed fast-twitch muscles and shrunk so that it didn't need much food to become self-sufficient. Meanwhile, the koala developed whatever the opposite of fast-twitch muscles are, and became a slow moving, constantly sleeping machine of eucalyptus consumption that kind of looks like a teddy bear.