For decades, a bizarre, grub-like creature called Hallucigenia has stumped experts.
But next week a true likeness of 505 million-year-old animal will be unveiled at the Palaeontological Association's annual meeting in Cambridge.
The reconstruction has been put together by Desmond Collins, senior curator at the Royal Ontario Museum in Canada, and is based on recently unearthed fossils.
The first specimens were dug up in the early 20th century in the Canadian Rockies, amid a host of other fossilised soft-bodied animals.
In the 1970s, Simon Conway Morris, then a Cambridge University graduate student and now professor of evolutionary palaeobiology, wrote a description of the creature and gave it the name Hallucigenia to reflect its "dream-like appearance".
His suggestion that it was a small spindly creature that walked on pairs of spines with a row of tentacles on its back and a globular head sparked a series of reinterpretations.
It was repeatedly redrawn, flipped upside down and back-to-front as palaeontologists struggled to make sense of its cryptic fossils.
Dr Collins believes Hallucigenia was 1cm-3cm in length, armoured with seven pairs of robust spines along its back and seven pairs of long thin legs that ended in large claws.
It had a small head on the end of a very thin neck with two fang-like projections, two short horns and possibly a pair of eyes.
Hallucigenia is considered to be an onychophoran and its closest relative is the velvet worm, a carnivorous scavenger that lives in rainforests.