It wasn't an easy exercise, seeing how he was in a cage designed to keep him out at all costs. However, Sam Tenaz had been made into his perfect vessel and it was a little like being pulled by a magnet. Lucifer had to essentially put himself into a trance and then he managed to have a small part of his self follow that magnetic pull.

He ended up floating over the water. Early days. Shortly after creation. He could tell by the smell in the air. The feeling of it all. New, brand new. What was Sam doing with a dream like that?

He realised there were a few ways to go about it. Lucifer, being Lucifer, decided to go with the path of destruction. He manifested on a beach, picked up a stone and hauled it at Sam, flying above him with those blue-tinted wings that weren't his. Sam was screaming as he came crashing down into the sea.

Lucifer figured that might draw out the guardian angel.