Rain brings life, especially in the more notoriously arid environments. Plants flourish, animals thrive and life abounds after water hits the earth.

But one very particular form of life has been waiting for just the right conditions to make itself known, and a late July monsoon in northern Arizona was just the ticket.

The discovery took place at an ancient ceremonial ball court at the Wupatki National Monument, located near Flagstaff, Arizona.

“The ballcourt is full of water after the recent rains here at Wupatki,” the Wupatki National Monument Facebook page shared on July 26. “It’s easy to see how people could have used this as a water reservoir 900 years ago. Wildlife still come to drink from it today.”

As the water continued to stick around in the 102-foot-long pool, reports of “tadpoles” started coming in. Lead Interpretation Ranger Lauren Carter thought that sounded plausible, explaining that toads could have come out of their protective burrows to lay eggs when they realized the conditions were conducive to rearing young.

But the reports kept coming in, so Carter decided to go herself and check it out. What she discovered was something much more interesting than toads.

“We knew that there was water in the ball court, but we weren’t expecting anything living in it,” Carter told Live Science. “Then a visitor came up and said, ‘Hey, you have tadpoles down in your ballcourt.’”

“I just scooped it up with my hand and looked at it and was like ‘What is that?’ I had no idea.”

The creature in her hand looked like a throwback to a fossil: It was pink, shaped like a horseshoe crab and had three eyes. Carter soon realized they had Triops, also known as “tadpole shrimp” or “dinosaur shrimp.” Triops means “three eyes” in Greek.

“We have shrimp in the ballcourt!” the WNM page updated on Aug. 4. “Well, sort of. We were getting reports of tadpoles in the standing pool of water down in the ballcourt on the Wupatki Pueblo trail.

“This would not be unusual since the recent rains have brought up the toads from their underground burrows. However, upon investigation by rangers we found something entirely different and somewhat unexpected.

“Tadpole shrimp, also known as Triops, are technically neither tadpoles nor shrimp, but they ARE crustaceans. Triops is a genus of small crustaceans in the order Notostraca. They live in vernal pools in Africa, Australia, Asia, South America, Europe, and some parts of North America. They are sometimes called living fossils because their outward appearance has changed very little since the Triassic.

“How do crustaceans live in such dry conditions? They have a very specialized adaptation that allows their eggs to survive being completely dry for long periods of time. These little horseshoe crab looking critters lay in wait until a pool of water remains long enough for the eggs to hatch. Then they gorge themselves, grow to adulthood in just over a week, breed, and lay more eggs to repeat the cycle. They are also food for birds such as nighthawks here in the monument.

“Triops are just another example of how even in the harshest conditions, life finds a way.”

In the comments under the post, WNM also explained that the crustaceans average two to three inches in length and their eggs have been observed to remain dry for up to 27 years before hatching. They also said that though the ball court has been filled with water for a week “twice now over the last four years,” they “haven’t noticed the Triops before now.”

Though the find left observers stunned, the birds wasted no time gorging on the unexpected feast. Rangers have no idea how long they will have to wait for the next good monsoon to see these fascinating creatures again.