A mysterious object that is just 4,000 light years away from Earth is unlike anything ever seen before in space, astronomers have said.
They think it could be a neutron star or a white dwarf – collapsed cores of stars – with an ultra-powerful magnetic field, also known as a magnetar.
As it spins through the cosmos, the 'spooky' object sends out a beam of radiation, and for one minute in every 20 it is one of the brightest objects in the night sky.
Observations show it releasing a giant burst of energy three times an hour.
'Spooky': A mysterious object that is just 4,000 light years away from Earth is unlike anything ever seen before in space, astronomers have said. Pictured is an artist's impression of what the object might look like if it's a magnetar, which is an incredibly magnetic neutron star
Neutron stars are the collapsed, burnt-out cores of dead stars.
When large stars reach the end of their lives, their core will collapse, blowing off the outer layers of the star.
This leaves an extremely dense object known as a neutron star, which squashes more mass than is contained in the sun into the size of a city.
A neutron star typically would have a mass that's perhaps half-a-million times the mass of the Earth, but they're only about 20 kilometres (12 miles) across.
A handful of material from this star would weigh as much as Mount Everest.
They are very hot, perhaps a million degrees, highly radioactive, and have incredibly intense magnetic fields.
This makes them arguably the most hostile environments in the Universe today, according to Professor Patrick Sutton, head of Cardiff University's gravitational physics department.
The dense objects, in particular their cores, are key to our understanding of the universe's heavy elements.
The mysterious object that has just been discovered could also be a magnetar, which is an incredibly magnetic neutron star.
Astrophysicist Dr Natasha Hurley-Walker, from the Curtin University, International Centre for Radio Astronomy Research (ICRAR) in Australia, led the team that made the discovery.
Her team was mapping radio waves in the universe when they came across the potential 'magnetar'.
She said: 'This object was appearing and disappearing over a few hours during our observations.
'That was completely unexpected. It was kind of spooky for an astronomer because there's nothing known in the sky that does that.
'And it's really quite close to us — about 4,000 light years away. It's in our galactic backyard.'
Dr Hurley-Walker added that the observations match a predicted