This disgusting stuff was almost completely covering one poor little watermelon seedling (look closely in the center of the above photo). When I poked the stuff with a stick, it was soft & gooey and mustard-yellow in the center. Just gross.
I took these pictures planning to post a "what the heck" question but I decided to see if I could figure it out myself. Amazingly when I Googled "garden Colorado yellow slimy" I actually got useful results! After clicking a result titled "Yellow Goo in your Garden" from CSU's Extension office, I had a name to search. Slime Mold.
The next article from CSU (The Slime Molds) describes the mold as resembling dog vomit. I knew I had the right answer then! Actually, after reading the article, I'm almost wishing I hadn't poked it apart as much as I did (before I hosed it down pretty well to free the poor melon). It really is sort of interesting. I did have to laugh at the end of the article where it says "Like nature's other organisms, slime molds should be looked at for their beauty and enjoyed as one enjoys a mass planting of dianthus or snapdragons". I'm not so sure I'd go that far...
