Pluto's 'almost twin' dwarf planet Eris is surprisingly squishy 

 Pluto's 'almost twin' dwarf planet Eris has a rocky core blanketed by an icy shell, which appears to be flexing slowly. 

https://cdn.mos.cms.futurecdn.net/5wA9HMEuB49dhKPdfv3Vd9.jpg

https://www.space.com/pluto-twin-dwarf-planet-eris-squishy