I used to think octopuses were already weird enough.
Then I watched footage of a mimic octopus in Indonesian waters doing something that honestly made me question what I knew about animal intelligence. The creature—brownish, roughly the size of a large apple—was gliding across the seafloor when a damselfish approached. In maybe two seconds, the octopus flattened its body, stretched six of its arms backward, and raised two forward like venomous spines. It looked exactly like a lionfish. The damselfish turned and bolted. Once the threat passed, the octopus just… resumed being an octopus, as if nothing had happened. Here’s the thing: this wasn’t some accidental resemblance or lucky camouflage pattern. This was deliberate, dynamic impersonation—and it’s far from the only trick in this animal’s repertoire.
The shape-shifting cephalopod that rewrites the rules of underwater deception
Mimic octopuses, scientifically named Thaumoctopus mimicus, were first described in 1998 off the coast of Sulawesi. They inhabit sandy, murky estuaries and coastal waters across Southeast Asia—places where visibility is low and predators are plentiful. What makes them extraordinary isn’t just their ability to change color and texture like other octopuses, but their capacity to actively imitate the shape, movement, and behavior of at least fifteen different species. We’re talking flatfish, sea snakes, jellyfish, stingrays, crabs, mantis shrimps, and more.
The mechanics are equal parts biology and theater. Octopuses have no bones, which means their bodies are almost infinitely malleable. They can compress into crevices the size of a quarter or stretch their arms to several times their resting length. Their skin contains millions of chromatophores—pigment cells controlled by muscles—that expand or contract in milliseconds to change color. Beneath those sit iridophores and leucophores, which reflect light and create texture. But mimicry requires more than hardware—it requires the octopus to choose which animal to imitate based on context, threat level, and availabe escape routes. That’s cognition.
Wait—maybe the most unsettling part is how context-dependent their choices are.
When a mimic octopus encounters a territorial damselfish (a small but aggressive fish), it often imitates a banded sea snake, a known predator of damselfish. When it needs to traverse open sand, it might flatten itself and undulate like a sole or flounder, blending movement with the environment. If a larger predator approaches, the octopus has been observed imitating a jellyfish—arms trailing, body pulsing—which many predators avoid due to stinging cells. Marine biologists like Dr. Mark Norman, who co-authored early studies on the species, noted that the octopus seems to assess the threat and select the most effective deterrent. It’s not random. It’s strategic.
When evolution hands you a toolkit this absurd, survival becomes performance art
There’s still so much we don’t know, which is maybe the most frustrating part. Do mimic octopuses learn these behaviors through observation, or are they hardwired? How do they recognize which predator they’re facing in murky water? Some researchers believe they rely on chemoreception—tasting the water for chemical cues—but that’s speculative. Others think they may have an innate library of defensive postures that get refined through experience. Honestly, we’re still scratching the surface.
What’s definately clear is that this ability isn’t just about survival—it reveals something deeper about cognition in invertebrates. For decades, scientists assumed complex decision-making required a centralized brain structure like ours. Octopuses have nine brains—one central and one in each arm—and roughly 500 million neurons, about as many as a dog. But their intelligence is distributed, decentralized, almost alien. They don’t think the way we do, yet they solve problems, plan ahead, and apparently run through a mental Rolodex of predator profiles before choosing a disguise.
I guess what gets me is the improvisational quality of it all. This isn’t instinct in the rigid sense—it’s adaptive, reactive, creative. A mimic octopus in a lab setting was once observed imitating a coconut shell rolling along the seafloor, something it couldn’t have encountered in evolutionary history. It saw an object, assessed its usefulness, and became it. That’s not just mimicry. That’s improvisation.
Anyway, the next time someone tells you intelligence requires a backbone, show them a video of a mimic octopus pretending to be a stingray while simultaneously changing color to match the sand and adjusting its movement to simulate a gliding motion. Then ask them to reconsider.
