It all depends what it looks like.....

If it's green in colour then it's probably an algae like Nostoc commune:

http://www.fugleognatur.dk/wildaboutdenmark/gallery_wad.asp?mode=ShowLarge&ID=49788

Or it might be one of the jelly fungi:

http://www.google.co.uk/images?q=jelly%20fungus&um=1&ie=UTF-8&source=og&sa=N&hl=en&tab=wi

or a slime mould

Other possibilities are water-retention gel (from a pot plant perhaps?) or cat deterrent gel or the oviducts of frogs or toads left behind by an animal (fox, badger, buzzard.... though we have the same result from the local Heron) feeding on the amphibians and rejecting the inedible parts.