What's in the mulch you've got spread around there? My guess is that that's some kind of fungus that is helping to decompose the mulch.

I don't think it's a problem, other than the fact that it looks a little odd.

No clue. The mulch has been there for months, although that's normally where I set the dog poo until it goes out in the trash, so I fugess it could be related to that somehow. Just freaked me out with how quickly it grew....

This stuff is harmless. Read about it on this link but don't use his control method.

Here is a link that might be useful: Gardenline

Not a mold, not a fungus, but is certainly one of the 'creatures' we call slime molds. (confusing, I know)
They creep along surfaces, feeding on organic compounds, but actually probably do little to help anything decompose. They don't stick around long enough. Plus, they'll move across totally inert surfaces like your siding, rocks, sidewalks, etc.

Completely harmless to anything, you should not spray or pour solutions that could contaminate the soil. Spray it with water or remove it with a shovel.

I had this happen in one of my raised beds this week. Same bed two spots a few feet apart. Grew overnight to about 2ft square. I removed it w/ a hand shovel and put it in a cooking compost pile. I covered the areas w/ corn meal incase it was fungus, which I guess it isn't. I just didn't want it to take over my cucurbits.

Funny how the slimiest gobs of goo are the least important. Dog barf fungus is another one you can ignore and it goes away.

Having said that, my wife's African violet got a white, fluffy soil fungus and the soil became very acidic. The plant started to rot a the soil line. I treated it with milk and the plant pulled through.

That is a slime mold commonly called "Dog Vomit Fungus" because that is what it looks like.

It is harmless.. but not that once it drys and browns.. that the slightest disturbance will cause it to puff ... like puff ball mushrooms.

Again usually not a problem, but i had a huge patch of it behind a bush in a corner area against my house.. i go to water around that area and the water caused it to puff out.. i had to back off the area because there was so much "puff" spores in the air... i assume it isn't the best breath to much in.

So now i just flip it upside down once it drys out. It is interesting though.. you can sometimes see bright orange versions too.

the end.

This web site might provide some good information for those interested.

Here is a link that might be useful: Tom Volk on Slime Mold

could this be dangerous for my dogs if they eat it? i scooped it out as soon as i found it, but we have a large back yard and my lab mixes eat everything they can find

As Tom Volk writes in his article linked above, "There is no known danger to humans or other animals from inhaling the spores or ingesting this organism, although I don't think you will have a pleasant dining experience if you decide to try it-- I do not recommend it."
There is no reason to "scoop" this up and toss it, other then for cosmetic purposes.