Swims, flies, and spread disease
What’s your biggest fear? Ours is having a rat climb out of our toilet pipes, jumping out of the water, and taking a huge bite out of our buttocks when we least expect it. Oddly enough, our greatest fear almost became this person’s reality. However, the rodent didn’t look like an ordinary rat, so he asked the internet what was up with this creature.
It took no time for someone to inform the OP that this rodent was actually a flying squirrel. How it got in through the bathroom, nobody has the slightest clue. But a disease-spreading creature that can fly sounds like an update to our greatest fear.