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, Informative) by takyon on Thursday January 03 2019, @04:09AM
I definitely see what could be flatness in the big lobe in this GIF, while the smaller lobe appears more round:
https://en.wikipedia.org/wiki/File:UltimaThule_TwoCloseups.gif [wikipedia.org]
There is another press briefing at 2-3 PM EST tomorrow. Hopefully we get a new photo or two along with the composition data.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]