Ok, with very little hints to go on besides the picture, What is it? The picture above was teased this morning from the Forgeworld Bulletin.
You can check out the rest of the Forgeworld bulletin this morning, which has some excellent painted Horus Heresy models on it painted by Mark Bedford.
via the Bulletin
"Mark Bedford’s been busy working on the Knights and Battle-automata that are making up his Dark Mechanicum force. Their hulls are the shade of weathered bone, which looks great contrasting the dark metal. Mark’s just added a Domitar Battle-automata to his already impressive force."