Personally I would say it would be wiser to just have him pay you back for the snake, as a personal loan, over doing co-ownership. Then charge him for feeding while it's in your care, and worry about splitting the clutches later.

Or at least write up a contract, leave an option for him to buy your share of the snake off of you, and take it to a notary. But definitely don't do a verbal contract, and always have a way of getting out of a contract.

I had a verbal contract with a friend about creating a videogame (my game) and running the business (his end) but later realized he was bloody crazy (wanted to kill everyone who wasn't part of some cult he was starting). I was glad it was a verbal contract then

But verbal contracts are, as stated, a bad idea.