Included is a photo of something that comes overnight, it is weird, I have a small dog and would it be harmful if she ate it.
This is called slime mould, or ‘dog vomit’! It is a very primitive organism similar to fungi and bacteria. It normally forms a gel-like ooze on the soil surface and it can slowly move along feeding on bacteria and other micro-organisms. In autumn, it sometimes forms spore-bodies of yellow or white which grow on the grass for support. These turn black when the spores are released. It does no harm to the grass, and is not poisonous for dogs, as far as we know.