Why does my world in some areas randomly do this? (The clouds of fog everywhere and dimmed screen)

Arena check (just making it before I get into hard mode)

Is this good or do I have to space out my platforms more?

i found unicorn and harpy (and crab) in an underground house???? this is prehardmode, and i have now clue why this happened. can anybody help??? no cheating or tediting going on here? when i died they respawned in the same position, can i farm them?

Got the dirtiest block pet less than 30 minutes in

Saw a post asking what rare item dropped way too easily for you and decided to post this screenshot from oct 7th 2022. For anyone wondering the world is medium size

New golem buff just dropped

Got this little guy while mining dirt

I destroyed 3 shadow orbs for loot, then I teleported home, and now the eater of world decided to go off into space.

please help

Cthulhu Pixel Art

My meteorite fell into one of the holes of my corruption biome.

Need help with mechs

Going to sum this up I want to beat mech bosses never done it before the main things I feel like I need is a better summon a sentry if possible and a few more pots like iron skin and the max hp anything I should get to fight either destroyer or twins?