Mushrooms are the fruiting bodies of a large underground web. Various mushrooms fruit at various times of the year, most often when the soil is wet -- if it has rained a lot in your area in the past week or two that may be a factor. Many fruit in the late summer and fall after the summer drought. Most mushrooms fruit for only a short time.

It is hard ot get rid of them as you need to destroy the underground network which can cover several city lots and it will require chemicals which are likely to more toxic to your pets than the mushrooms are.

If you don't like them, pick them and add to the compost pile. To identify most mushrooms you need a good field guide, a magnifying glass and an expert by your side. Dogs and cats are unlikely to eat mushrooms unless they have been fried in butter first.

Keilamarie, in case you want more information, I've seen postings about mushrooms on the forum I've linked to below.

Here is a link that might be useful: Moss, Ferns & Cryptogams