Guys, you can't eat the gray dog because its the biggest dog on the field, you can never eat biggest dog on field, once 3rd dog comes out you can eat gray dog
adding on to the 'how to beat last boss', I beat him by the time he got to my trap: do everything they tell you, but spam up hobbits and elves to slow down and get some hits in. It helps alot. also make sure you get a barrier up