Alongside modern spider traits such as a silk-producing structure called a spinneret, it possessed a remarkably primitive feature: a whip-like tail covered in short hairs that it may have used for sensing predators and prey.
Before arachnophobes take one look at the recently-identified beast and hide away in a dark room, scientists say it would hardly be a threat if it still stalked the Earth, with an emphasis on the if.
While creeping through the dinosaur-era forest, four spiders became enveloped in a pool of tree resin oozing from conifer trees.
Though Dr. Selden and his colleagues agree it's possible C. yingi may have been a part of the Uraraneida group, they also suggest that it could earn its own branch on the evolutionary tree right between spiders and Uraraneida.
At 3mm, the tail extends beyond the newly christened Chimerarachne yingi's 2.5mm body and the global scientists behind its discovery say it links today's spiders with those that lived before dinosaurs.
The extraordinary finding is described in Nature Ecology & Evolution by an global team of boffins in the Hukawng Valley, Myanmar.
"We have known for a decade or so that spiders evolved from arachnids that had tails, more than 315 million years ago", Russell Garwood of The University of Manchester, a co-researcher on the study, told the BBC.
100 million years ago, spider-like critters had fancy long tails to go with their fangs and spinnerets.
Research papers detailing the discovery, which were published in Nature, are clear about one thing: C. yingi isn't a spider, but it's also not far off. Arachnids have a twisted history, and paleontologists know that some of the closest ancient relatives to spiders didn't survive through to the modern day.
The amber has often traveled to China, where dealers have been selling to research institutions.
"Already, we've got some other primitive spiders from this amber", Selden says.
The telson is something we see it today in scorpions - but it has never been known before in a spider. "Egg-wrapping is a vital function for spider silk, as well as laying a trail to find its way back home". "It all depends on where we decide to draw the line", Selden said.
"However, like all spiders it would have been a carnivore and would have eaten insects, I imagine", Seldon said. I presume that it didn't make webs that stretched across bushes. However, according to Seldon, there is a possibility of descendants of the creepy tailed spiders living in southeast Asian forests even now. The animal itself is only two and a half millimeters long, with its tail reaching three millimeters.
Other species of insects, including millipedes and modern spiders, were also found alongside the four chimaera fossils.
"It makes us wonder if these may still be alive today". Those areas aren't very well studied, and since the creature is too tiny, it could easily go unspotted.