What could this be on the soil in my garden?

[demola]

Hello everyone and good morning. I noticed this fungi like substance in my garden last week and I still find it here this week.
It begin as a neurno- like whitish web-like thing on the soil. After a while it turns yellow and then brown.

There are times it affects some grasses around. I don't really know how to describe this as it's strange.

Please find pictures below.

[demola]

First time I found it in my garden. How it looks like.

[demola]

After some days it changes to below

[demola]

then when it fnally turns dry: It then leaves some spots on the grases around.

[demola]

Does this have any negative effection the soil and the plants? Please share your opinion. I had thought this was mycelium but I doubt.