So putting it all together...
Cart Of the Dead (Su): An ankou is followed everywhere it goes by an invisible cart pulled by an equally invisible ox or horse. The cart and its beast of burden produce noise and leave a trail of wheel-ruts and hoof-prints like a normal horse- or ox-cart would. The Cart of the Dead can travel over any terrain without any penalty, even rolling across or through water, and can carry a load of up to 1,000 pounds. The cart can only carry inanimate objects, which become as invisible and intangible as the cart itself. Only the ankou can load or unload the cart, but if the cart is dismissed any objects it is carrying regain physicality and fall to the ground. Neither cart nor beast can be damaged by any weapon or spell, although it can be dismissed from existence by an exorcism, dispel evil or a similar higher-level banishment spell. The ankou can resummon a banished Cart of the Dead the following night.
Edit: I know you liked the pun, Cleon, but I think most folk will think the ability name of "Cart Off the Dead" is a typo when we refer to "Cart of the Dead" in the description.