Ten foot long black snake? I think something like seven feet may be the limit unless you are thinking of a different snake than the ones I know.
Longest snake in North America – Black rat snake
Posted on Apr 24, 2012
How big can it get?
The longest recorded black rat snake is a shade over two-and-a-half metres (8 feet).
The biggest black rat snake ever documented in Missouri measured 84 inches. The longest on record anywhere was 101 inches — more than 8 feet.
When my children came running to the house to tell me what they saw, the snake was at least 20 feet long!!!
Thank you for raising the question.