There's no stupid questions, we keep bizarre alien like creatures in a glass boxes of saltwater, none of this should come naturally.
I have a few of those same polyps in my 120 gallon aquarium. I wouldn't have bought them but they rode in on some rocks. Your read correctly that they are very toxic, because of that I avoid trying to remove them or scrape them off the rock. If you're just starting out I would keep them, they are very hardy coral and can be fun to feed.
I am concerned that you said the tank is cycling but you already have an anemone. Most anemones are rather sensitive and can be difficult to care for if you're a beginner. Do you have a photo of the anemone, it would help us identify it's species and give you some extra care tips about it's specific requirements.
Welcome to the forums and good luck! There's a lot to learn but it can be really fascinating stuff sometimes!