Have you had anything applied to your lawn recently? Fertilizer? It looks like those hydrating gel particles you might find in lawn patch. They are small until they absorb moisture, then they swell up and look like those pictures. I'm not sure how they would have gotten there though.
Blue balls of jelly rained down on a man's garden in Dorset in January 2012.Upon further analysis these proved to be sodium polyacrylate granules, a kind of superabsorbent polymer with a variety of common (including agricultural) uses. They were most likely already present on the ground in their dehydrated state, and had gone un-noticed until they soaked up water from the hail shower and consequently grew in size.
Haribo Gummi Globs