What happened when Moses put his hand inside his cloak?

Answer: It became leprous

When Moses took his hand out of his cloak it was leprous, white as snow; when he put it back it was restored.

“Furthermore, the LORD said to Moses, “Put your hand inside your cloak.” So he put his hand inside his cloak, and when he took it out, his hand was leprous, white as snow.”— Exodus 4:6 (BSB)