The new troop is the leaked Air Tank that was first seen in one of godson's videos. Some of the new troop files are already in game, that's how we have gameplay video of it:
http://youtu.be/WS4xp2436FU?t=1m48s
the person who made the video used offline mod to use the hidden troop. Obviously the animation isn't the same, but the idea of the troop is.
If you decrypt the Animation.csv file, you can see each troop first(prototype) name. such as: "Boar Rider"(Hog Rider), "Warrior Girl"(Valkyrie), "Gargoyle"(Minion) etc... The last troop in this file is "AirTank".
About the troop - It has three detachable engines. All engines have to be detroyed to take down the air tank. Each falling engine causes damage.
What else we know about it: A dark troop, available in lvl 6 dark barracks and th9.