Bugs? Worms / weird alien? Need help ASAP!!!

[Crabs McJones]

Why do you need help ASAP? Are they eating your face off or smthg?

User is unfamiliar with the creature they are dealing with. So asking for an answer as soon as possible is not unjustifiable. But it looks like @ndrwater nailed the ID ;)

 

[vetteguy53081]

I see most normal hitch-hikers. Can remain or you can start with stars. They multiply quickly by simply breaking off one of their legs and growing into a new one and often. The work is a bristleworm. They keep the bedding opened/loosened. I personally don't want them in my tank.

 

[markfmvl]

any idea what those red tubes / spikes on my rocks are?

Vermatid snail. Not sure why they call them snails. They send out a long mucus string to snag food then reel it in to eat.