You can't tell this is made of felt at a glance, so it would make the perfect prank on any visitors who have small children. Then again, it costs $500, and that prank isn't that funny. [Vivaterra via Neatorama]
The most hilarious thing would be if you found a real stone that looked like these. Then, you could toss a fake one at someone to freak them out, and then when they realize it's felt, you peg them in the face with the real one.
They won't even duck. HaHA, Sucker!