What is this growing in my house?

I'm renting house in Southern California and just noticed this growing right next to the central heat/AC intake. Is this dangerous to my family and pets? Is it indicative of greater issues like water damage to the house?

Growing in our basement. I‘m sure I don‘t even want to know … how bad is it?

Took my first spore print (it wasn't that good lol)

Is this brown thing fungus?

Was watering my plants and I noticed this but Ive never seen this before.

ID

Found around 8500-9000 in Colorado early August. Reminded me of wood ear mushroom but didnt see any others like them the entire time foraging for chants

Found so much of this in the woods today

Favolaschia claudopus (orange pore) I think is now considered invasive in the U.K., and here in Cornwall it seems to be rapidly spreading everywhere. Shame as it absolutely beautiful.

What is this… fungi?

In the east coast of the United States if that helps.

What’s this guy in Maryland?

I.D help please

Found in Scotland (UK) under a Scots pine. Coastal. Approx 45-50mm (2" ish). I didn't pick it to get underside shots as there was only this only visible. Looked through my books and I can't find one similar.

Found this cool looking dude in nh wondering what it is

Id please! Willamette Valley, OR

Found in the Willamette Valley, OR. I poked it and it is a softer texture. Kinda looks muddy, but not. I think the tree it is on the roots of might be an oak?