Oyster mushrooms.

Fergus got two boxes of grow your own Oyster mushrooms for Christmas, one from his flatmate, Ailie, and one from his girlfriend, Keira. He shocked Ailie's box into growth (by plunging into cold water) a couple of days ago and it seems Keira's has erupted spontaneously at the same time. 

These are Keira's, the largest is about 1.5cm tall. 

Harmony has been restored.