The leech with big teeth which goes inside us especially gives me the creeps.
Houdini fly breaks through wall of bee nest to lay its eggs inside, by inflating its head.
What animal has the most brain proportionally speaking? If you think it's humans, you're far off. As animals miniaturize, their brains have to shrink more slowly, so they can continue to function. The tinniest spiders have 80% of their bodies filled up with nervous system.
Smithsonian researchers report that the brains of tiny spiders are so large that they fill their body cavities and overflow into their legs.
As the spiders get smaller, their brains get proportionally bigger, filling up more and more of their body cavities. "The smaller the animal, the more it has to invest in its brain, which means even very tiny spiders are able to weave a web and perform other fairly complex behaviors,"...
"We discovered that the central nervous systems of the smallest spiders fill up almost 80 percent of their total body cavity, including about 25 percent of their legs."
Interesting. Never realized that in order to function, small creatures need more room for brains, but it makes sense.
I've read that our skull size limits how smart we are, but I imagine in the future, we will change what evolution has given us and increase our brain size.
A caterpillar retains its head capsules, when it molts, forming a hat. Behold a larvae of a Gum Leaf Skeletoniser moth.