The mummy will follow (or go to) Tak in a straight line. Get the mummy to a spot where he can walk a straight line to the next white (rock) platform, and then hit him with the spirit stick to make him fall down and stop moving. Then, get Tak to that platform, and wait for the mummy to get up and move to catch up to Tak. (The mummy can walk through the fire.) Knock the mummy down again with the spirit stick, and then move Tak to the next white (rock) platform where the mummy can walk a straight line to catch up to him. It's kindof a zig-zag pattern to get back to the other side, and it takes a series of moves. But the key is to knock the mummy down so he only moves when you want him to move.