If I were to ask most students of evolution for an example of how strong selection can lead to ridiculous and extravagant behaviors or appearances, I would probably get an array of sexually-selected traits as an answer.
puffer fish dances, stalk-eyed flies. All of these are weird and wonderful examples of how sexual selection can produce some pretty incredible traits.
In contrast, we usually think of natural selection as favoring practical traits. For example, many small birds are streaky brown, all the better to avoid getting munched, but not super exciting to look at. Or, how a fishes mouth works to optimize foraging, pretty important stuff, but not terribly flashy. This makes sense, most of natural selection focuses on not getting eaten while getting enough to eat yourself.
But every once in awhile an example comes along that turns the usual pattern inside out. Meet the Cinereous Mourner from the Amazonian rainforest. It's a pretty boring bird, as far as rainforest birds go, and looks like it does a good job of not getting spotted by being plainly colored.
But, this is what the chick looks like. If you are a young bird trapped in a nest and unable to fly away, why oh why would you ever want to be so ridiculous? This makes no sense, right?
The trick is, this chick is a master of disguise. The picture below the chick is a large, hairy, and toxic caterpillar. When the chick puts it's head down, it looks a lot like the caterpillar. Plus, it moves like one. Go here to see the video, but it bobs it's head around just like a caterpillar looking for a leaf to eat. So if you are a hungry predator looking for a delicious nestling to eat, but stumble onto something that looks and acts like a deadly caterpillar, chances are good that you'll give it a pass and move onto something that looks less likely to kill you if you eat it. So in this case, a crazy exaggerated appearance and behavior is all about not getting eaten.
A great example of how strong selection can lead to some pretty amazing things. This is also a great example of something called Batesian mimicry, which is when something that is harmless acts like something that is dangerous, like milk snakes (not dangerous) and coral snakes (deadly).
Nice one evolution!