That sounds intriguing...how'd it taste...? (just kidding)

Any japanese beetle larvae* in your area? (short-fat grubs that develop under soil surface) Perhaps a bacteria or soil algae? Pictures would be great if it re-appears. What's the residue look like now?

* Control of Japanese Beetle Adults and Grubs in Home Lawns

Just a wild guess, lol.
Rusty Trichome Reviewed by Rusty Trichome on . Liquid sac at the base of the plant.... Has anyone else ever had a small sac of light green to cream colored liquid emerge from your soil? It was about the size of a nickle and when I poked it it broke open and leaked out, never seen that before. It was almost slimy looking. Rating: 5