ask the prince of puzzles

Casefile #0107
The Riddler

Casefile #0107

amashi-zaino asks: Dear Riddler. I know that this might not be the best riddle, but a friend of mine from Mensa told it to me once. He said that it needs some revision I want to ask the master. Who better to ask than the prince of puzzles. 50 is my first, nothing is my second, a snake will make my third, three parts a cross is reconed. To find out what i am put all my parts together. I am all your past and you fear me in cold weather. What am I? If you get lost I’ll be happy to give you a hint.