Well... thats very concerning that your neighbor uses 'poison' in and around his yard, since that can have a lot of unintended consequences for the wildlife... 

But more importantly this appears to be unrelated as I'm fairly certain this is a fungus (actually a slime mold if you want to get technical)...with the amounts moisture we've been having in the southeast of the state its very common to see this type of activity. The slime mold is actually breaking down organic matter in the soil which the plants will then bring back up as nutrients. It is far more common in mulch piles compared to in the lawns however.

You can rake it in or just leave it and it'll break down just so long as we keep getting rain...but it won't do any harm.

Thanks for sending in the question and photos!

https://mastergardener.extension.wisc.edu/files/2015/12/DogVomitSlimeMold.pdf