This here is Custos Cavum ("The Guardian of the Hole"), a fantastically weird robotic sculpture by artist U-Ram Choe on display at New York City's Asia Society until December 31, 2011. The piece was inspired by the 10th-century Indian sculpture, Shiva as Lord of Dance. From Choe's synopsis of the project:

Once upon a time, there were two worlds. They were connected to each other through a number of small holes, as if the worlds were breathing through these holes. However, the holes had a tendency to close up, so there were guardians next to each one to keep them open. The guardians were called "Custos Cavum."

They took the form of seals and had large front teeth, which they used to gnaw the holes to prevent them from closing up.

Whenever a Custos Cavum felt the generation of a new hole somewhere, it fell into a deep sleep. From the body of the quietly sleeping Custos Cavum grew winged spores called "Unicuses." These spores took flight and each flew to a new hole, where it gave rise to a new Custos Cavum.

As time went on, the people of each world gradually forgot about the other. The guardians lost their power and died, one after another. When the last Custos Cavum died, the last hole closed, separating the two worlds completely. The existence of the other world was entirely erased from people's memories.

Last night, I saw Unicuses start to grow from the last bone of a Custos Cavum in my small garden. According to an old story, Unicuses will grow whenever the holes to the other world are open again.