Shia LaBeouf 2. There are two pieces of the Allspark cube left: the military has one under lock and key, and Sam discovers another. The Decepticons steal one and bring Megatron back to life. But when Sam (Shia LaBeouf) wants to bring back Optimus, he has to find the Matrix of Leadership on the other side of the globe. Why not use the other piece? Mikaela (Megan Fox) has it in her backpack the whole time. It brought his kitchen appliances to life, why can't it do the same for Optimus?