There are three main 'webbed' mutations of cannabis that you can find if you search:
DucksFoot, bred and/or stabilized by Wally Duck Seeds. It really looks like the footprint of a waterfowl.
Aussie Bastard Hemp, a mutation from Australia, and its derivative Dizzy, which is a very strange crumply randomly-shaped leaf form with a low THC content. Work with these mutations is being done, and a very dedicated breeder whose work can be found on ICMag has brought it to a form where it is quite valuable as a hash crop.
Maple Leaf Indica, which has the least outrageous of the leaf shapes on this list. I do not know where to get it these days.