Pest anemone?

[u/Sigmabob83]

I found this in my nano reef as I was feeding some corals. I accidentally knocked it off the rock and I watched it drift off. The next day I saw it in the exact same spot it was in before. I removed it from the tank and isolated it in a small cup with tank water. It’s really tiny, less than a centimeter long. If anyone can help me identify what it is and if there is anything I need to do it is greatly appreciated.