Quantum and biological systems are seldom discussed together as they seemingly demand opposing conditions. Life is complex, ‘hot and wet’ whereas quantum objects are small, cold and well controlled. Here, we overcome this barrier with a tardigrade—a microscopic multicellular organism known to tolerate extreme physicochemical conditions via a latent state of life known as cryptobiosis. We observe coupling between the animal in cryptobiosis and a superconducting quantum bit and prepare a highly entangled state between this combined system and another qubit. The tomographic data shows entanglement in the qubit-qubit-tardigrade system, with the tardigrade modelled as an ensemble of harmonic oscillators or collection of electric dipoles. The animal is then observed to return to its active form after 420 h at sub 10 mK temperatures and pressures below 6 × 10 − 6 mbar, setting a new record for the conditions that a complex form of life can survive.