The notion of things within things can easily captivate our minds—just like the movie Inception, where dreams are nested within dreams within dreams. Almost everyone has experienced the curious sight of one mirror reflecting another, creating an endless tunnel of mirrors. This repetitive concept is known as mise en abyme, and the infinite version that occurs with mirrors is called the “Droste effect.”
However, it turns out that humanity wasn’t the first to explore such a concept. Nature has been embracing this meta idea all along.
10. The Imitator of Imitators

Mimicry is widespread in nature, but perhaps no creature does it better than the mimic octopus, which we’ve highlighted before. To give you a quick refresher, this remarkable octopus can convincingly mimic up to 15 different species, including fish and sea jellies. There are numerous videos online showcasing this skill, and it’s truly breathtaking to witness.
This is why Godehard Kopp, a German researcher, was so taken aback in 2011 when he observed a mimic octopus being imitated by a fish. The fish in question was a jawfish, which cleverly waved beneath the octopus to resemble a tentacle while it scoured the sea floor for food or shelter. This marked the first time a mimic had been observed mimicking another mimic, and the first known instance of a jawfish displaying any form of mimicry.
9. A Mouth Within A Mouth

The concept of a mouth inside another mouth became well-known through the movie Alien and also appeared in Monsters, Inc. TV Tropes refers to this as a “nested mouth.” In nature, this phenomenon exists as a pharyngeal jaw, which is essentially a second set of teeth located at the back of the mouth, designed to grip or tear food once it passes the initial set of teeth.
The most notable example of a pharyngeal jaw can be found in the moray eel. Its inner jaws lunge forward into the mouth, grabbing and pulling in whatever it’s consuming. This adaptation evolved as a replacement for suction, which the eel’s body structure and lifestyle made impractical. It also enables the eel to consume larger prey. And for those looking for nightmares—yes, they’ve been known to attack humans.
8. Remarkable Geological Features

Lake Manitou holds the title of being the largest lake in the world located on an island in a lake. It can be found in Lake Huron, one of North America’s Great Lakes, situated on the island of Manitoulin. Additionally, Lake Manitou has several islands within it, creating a fascinating sequence of islands in a lake, in an island, in a lake. And yes, we’re not the first to make the Inception comparison. However, it’s not the only geological wonder with this intriguing quality.
Taal Volcano, located in the Philippines, is a unique phenomenon—a volcano island nestled inside a lake, which itself is located inside a larger volcano. This makes it the world’s only volcano within a volcano. Taal also contains its own lake, and within that lake is an island called Vulcan Point. So, to wrap your head around it, Vulcan Point is the largest island inside a lake, within an island, that sits inside a lake, which itself is within an island. It’s small, though, and probably not suitable for habitation. Furthermore, Taal is still an active volcano, so it’s also quite dangerous. If you're seeking safer options, you might want to consider Manitou, where you could buy an island complete with a couple of charming houses already in place.
7. Secondary Endosymbiosis

In biology, symbiosis refers to the state of living together in a mutually beneficial relationship with another organism. Endosymbiosis, however, takes this to the next level by describing the phenomenon of one organism living inside another, often within its cells. For example, certain bacteria reside inside the cells of insects. But there’s a twist—some bacteria live inside the bacteria that are already residing within insect cells. These are a type of gammaproteobacteria, the same bacteria responsible for diseases like plague and pneumonia. This unique form of living inside something that lives inside something else is called secondary endosymbiosis.
What’s fascinating about endosymbiosis is that the bacteria residing within a cell can eventually lose their original identity. This is how mitochondria, the powerhouse of human cells, came to be. They were once bacteria that entered the cells of our ancient ancestors and ultimately became an integral part of them.
6. Hyperparasites

Parasites are incredibly abundant, likely making up the majority of species on Earth. Humans alone play host to over 100, and we’ve covered both helpful and terrifying examples in the past. So, it probably won’t come as a shock that parasites themselves have parasites—these are known as hyperparasites.
Some hyperparasites even have their own set of parasites, known as tertiary hyperparasites. You can see where this is going. Take, for example, Entedon albitarsis, which is a parasite of Pteromalus egregius, which in turn parasitizes Monodontomerus aereus, which itself infests Apanteles lacteicolor, a parasite of the brown-tail moth. This makes Entedon albitarsis a quinquenary hyperparasite—a parasite of a parasite of a parasite of a parasite. You really have to feel for the brown-tail moth in this case.
5. Evolving The Ability To Evolve

The core concept of natural selection is fairly straightforward. Giraffes' ancestors are a classic example in biology lessons because it’s easy to grasp that longer necks meant better access to food. Those with longer necks had more offspring that weren’t quite giraffes, and so the process continued until we arrived at the giraffes we know today. We can say these ruminant ungulates “evolved” long necks—it’s simple. Plus, long necks come in handy for epic giraffe battles.
Recent research has revealed that animals don’t just evolve specific traits—they also evolve the ability to evolve traits. This means they evolve their own “evolvability.” In a study on the bacteria responsible for Lyme disease, scientists examined regions of the DNA strand that don’t directly affect survival, but influence how proteins may change in future generations. They discovered that natural selection favored genetic diversity, even when no immediate survival pressures were present.
The researchers believe this concept may be more challenging to observe, and possibly less likely to manifest in larger animals. Sadly, they haven’t commented on whether natural selection could eventually evolve the ability to evolve the ability to evolve.
4. Moons In Rings

Saturn is famous for its vast number of moons, but its iconic rings, first observed by Galileo in the early 17th century, truly steal the spotlight. These rings are the most impressive in the solar system, and the moons reside within them. In fact, Saturn’s largest ring, which also happens to be the largest in the entire solar system, is fed by material from the moon Enceladus.
Rhea, Saturn’s second-largest moon, has sparked interest due to findings from the Cassini probe, which suggest it might have rings of its own. Although these rings haven’t been seen directly, measurements from Cassini’s instruments have detected Rhea’s magnetosphere. The data suggests the presence of “grains and boulders up to several decimeters in size” orbiting Rhea, creating what might be an equatorial debris disk—essentially, rings of a moon within the rings of a planet.
3. Universe Within A Universe

One intriguing theory, proposed by theoretical physicist Nikodem Poplawski to address certain black hole mysteries, suggests that our universe might be nested inside another universe. Dr. Poplawski, from the University of New Haven, Connecticut, posits that each time a black hole forms, a new universe may emerge within it. As he explains, “our universe could have itself formed from inside a black hole existing inside another universe.”
He argues that his theory offers explanations to several major mysteries, including the nature of dark energy and the origin of the Big Bang. His theory also successfully integrates both general relativity and quantum mechanics, two fields that have long proven difficult to reconcile. In his view, our universe could be part of an endless sequence, residing inside a black hole, which in turn is inside another universe, and so on—and similarly in the opposite direction.
2. Crater Within A Crater

The moon is pocked with craters, many of which contain additional craters. These features are helpful for dating purposes—the more craters nested inside a larger crater, the older the outer one. But craters within craters offer more scientific insights beyond just age.
During the moon’s early history, a massive asteroid struck it, forming the largest crater on the moon: the South Pole-Aitken Basin. Not long after (in cosmic terms), another asteroid collided within that original crater. The impact formed a secondary crater known as the Apollo Basin. One researcher likened the phenomenon to going into your basement and digging another hole.
This phenomenon is more than just an interesting anomaly; the double impact has created a crater so deep that it provides a rare window into the moon’s inner crust. Much like on Earth, the deeper we are able to observe, the more we can uncover about the early days of our solar system.
1. A Nest Within A Nest

The rufous woodpecker exhibits an unconventional nesting strategy. Its primary food source is the acrobat ant, a species that builds its nests in tree hollows. Rather than constructing its own nest nearby, the woodpecker breaks into the ants' home and builds its nest there instead. The ants, seemingly unbothered by this intrusion, allow the woodpecker to carry on, using this ‘nest-in-a-nest’ to raise its young.
The woodpecker isn’t alone in adopting such an arrangement. House sparrows also create nests in abandoned wasp nests, but only after the wasps have perished in the winter. This clever choice offers protection, as mammals that might otherwise prey on bird nests tend to steer clear of wasp colonies.
