2014 MU69 has two nearly-spherical lobes and is a contact binary. The collision between the two lobes happened at a low relative velocity, causing little damage to the resulting object. The "neck" between the lobes contains brighter material which appears to be dust that has settled down the slopes that run towards the point of contact.
[Added BBC link -ed]
(Score: 3, Touché) by takyon on Thursday January 03 2019, @12:57AM
It's the coolest (literally) cleavage we've ever seen.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]