When the Drive-Thru clerk tells you you can't take your horse through the Drive-Thru, you naturally walk him inside to take a giant dump on the floor. That's why you were using the Drive-Thru in the first place. Does nobody understand how simple this is?
Here's a picture of the savvy lady in Manchester, England who got foiled in this conundrum. Along with a picture of the big shit. The alert McDonald's staff was able to scoop up the horse shit, bread it, fry it, have a cook rub his dick on it, then serve it up as a 20-piece to the next foreigner they all hated who walked into the restaurant.