An asteroid that looks remarkably like a hippo is zipping past the Earth today.
2003 SD220, as astronomers call it, won't be this close again for another 400 years.
"Do you want a hippopotamus for Christmas?" NASA's Jet Propulsion Laboratory wrote on Twitter. "You're in luck. Hippo-shaped #asteroid 2003 SD220 will fly safely past Earth."
NASA described it as looking "similar to that of the exposed portion of a hippopotamus wading in a river".
2003 SD220 is 1.6km across, and will be only 2.9 million kilometres away - close by astronomical standards.
It rotates only once every 12 days, which is slow for an asteroid, and it's wobbling.
"Known as 'non-principal axis' rotation, it is uncommon among near-Earth asteroids, most of which spin about their shortest axis," NASA said.
Images of the asteroid were taken by radar.
2003 SD220's last Earth fly-by was on Christmas Day (NZ time) in 2015, more than 10 million kilometres away.
According to Purdue University's impact calculator, if the hippo-shaped rock slammed into Earth at an angle of about 45 degrees it could create a crater about 22km across.