Story about koalas:
When I was a kid (around 16 years old) my folks took my sister and I on a trip to Hawaii. We signed up for a rainforest bike ride through some of the nature reserves on Oahu.
Our bike guide gave us these motorcycle helmets to wear. All of them had all kinds of deep scratches and marks all over the place. Some guy finally asked what we were all thinking, "Umm... do people wipe out a lot on this trail? Is this safe?" The bike guide assured us the trail was safe enough for any amateur rider to take easily.
It wasn't until we got deep into the nature reserve when our bike guide pointed out to us a bunch of koalas sleeping in the trees. "We're entering the portion of the forest with the eucalyptus trees. They were planted here from Australia at the request of the US government decades ago. When they realized that eucalyptus trees depend on koalas pruning them for survival, they brought over koalas from Australia. Thankfully, the accidental additions to Oahu's ecosystem have not upset the balance..."
Now riding directly in front of me was a lady probably in her 50s I'd say. Looked physically fit. While the bike guide was continuing to talk about the eucalyptus trees, a koala went WUMP! and fell right on top of the bitch in front of me like a goddamn bomb. She landed a good 5 feet away from her bike, and the koala landed in the other direction, made a squeal of some type, and scampered off into the bushes.
The tour guide stopped, made sure the lady was alright, and said, "Oh, yes. Now you all know where the large scratches on the helmets come from."