Weirdest fossils ever discovered: These bizarre prehistoric oddities will have you scratching your head

Fossils can teach us extraordinary amounts about prehistoric civilisations, wildlife and ecosystems. But sometimes they don’t appear to us in the form we might expect. Here, we’ve rounded up some of the weirdest fossils to have been discovered in recent years. 

The weirdest fossils ever discovered

Fossil poo

There’s even a dinosaur poop museum in Arizona, complete with 8,000 pieces of fossilised faeces – known as coprolite. They even have an enormous coprolite that is believed to have come from a tyrannosaurus rex. 

A fossilised nest of 15 baby dinosaurs

A 70 million-year-old nest of protoceratops andrewsi dinoasaurs were discovered in 2011 with evidence that 15 baby dinosaurs had once been inside it. They were found in Mongolia, where it was believed sand had drowned the juvenile dinosaurs while they were still alive. 

Fossilised vomit

A Danish fossil hunter came across some mysterious fragments, which he soon realised were pieces of regurgitated sea lily. This vomit was possibly produced by a type of fish 66 million years ago, a time when dinosaurs roamed the earth. 

Fossils encased in gold

A 450-million-year-old fossil was unveiled by scientists in 2024, preserved inside iron pyrite (fool’s gold). The golden fossil was a species of arthropod – an invertebrate animal related to scorpions and spiders – that had been spectacularly well preserved thanks to their gold casing. ‘They look as if they could just get up and scuttle away,’ remarked Oxford Associate Professor Luke Parry, who was a researcher on the discovery. 

Fossilised sperm

In 2015, prehistoric sex cells were discovered in the wall of a worm cocoon on Seymour Island in Antarctica. They were linked to ‘clitellata’, a class of earthworms and leeches dating from 50 million years ago, in the early Eocene period. The fossilised sperm was able to survive so long because the sperm became trapped in the wall of the clitellata cocoon before it hardened. 

• 100 million year old giant sperm is world’s oldest

An incredibly well-endowed fossilised crustacean

In 2003, a 425-million-year-old fossil was discovered in Herefordshire with the oldest penis on record. The crustacean was discovered by UK and US researchers and was named Colymbosathon eclectics, derived from the Greek for ‘astounding swimmer with a large penis’. 

• The world's weirdest penises – including a detachable one that swims off after a mate

A fossilised ancient squid halfway through a meal

Combined fossils were discovered by an amateur fossil collector in 2021 in a quarry in Germany, which showed a belemnite in the process of biting a crustacean. While it was doing this, it was bitten by a larger predator – possibly a shark – which killed it. The belemnite sank to the bottom of the ocean, the crustacean still in its mouth, died and eventually fossilised. 

More stories about fossils from the wildlife world: 

• Why are the cliffs of the Jurassic Coast filled with dinosaur fossils?
• A complete fossilised jaw from a prehistoric giant – found in a New York backyard – has got scientists excited
• Astonishingly strange half-a-billion-year-old slug discovered in China