When humanity inevitably self-destructs, taking much of the world with it, what will be left behind? According to some predictions, the answer is simple: LEGO bricks and tardigrades.

The Ultimate Survivor

There is no living organism more resilient than the tardigrade—a microscopic creature less than a millimeter long. As reported by The Guardian, these tiny but extraordinary animals have proven their ability to endure extreme conditions that would annihilate most other life forms.

In fact, our likely last survivor, Milnesium tardigradum, has already survived the vacuum of space as part of an experiment conducted by the European Space Agency.

Tardigrades can withstand radiation, extreme cold and heat, zero gravity, and even being shot from a gun. They have been frozen for 30 years in laboratory conditions and revived as if nothing happened. Most impressively, despite their near-invincible nature, they are also incredibly cute.

When German zoologist Johann August Ephraim Goeze first discovered them in 1773, he called them “little water bears.” These chubby creatures are also affectionately known as “moss piglets” because they are often found in moss and lichen under a microscope.

Their scientific name, Tardigrada, comes from the Italian scientist Lazzaro Spallanzani, who named them “slow walkers” after observing their distinctive movement on their four pairs of stubby legs.

Superpowers of the Tardigrade

The secret to the tardigrade’s unmatched resilience lies in its ability to suspend its metabolism and halt the aging process.

Evolved for aquatic environments, tardigrades require a thin layer of water around their bodies to survive. However, when exposed to extreme dehydration or freezing conditions, they enter a cryptobiotic state known as the “tun” stage. In this dried-out form, they can remain dormant for years—springing back to life as soon as they rehydrate.

With these near-supernatural abilities, tardigrades have survived all five of Earth’s major mass extinction events:

The Ordovician Extinction (443 million years ago)
The Devonian Extinction (359 million years ago)
The Permian Extinction (252 million years ago)
The Triassic Extinction (201 million years ago)
The Cretaceous Extinction (66 million years ago)

They have been around for at least 600 million years—long before Homo sapiens—and, most likely, they will continue to exist long after we are gone.