mlott, you'll lose anything else on the rock doing that, including the bacteria, but if it's not the only live rock then you'll be fine. Rinse it very well and let it dry out completely to get rid of the chlorine before putting it back in.
bio, looks like a strawberry ball anemone, which is actually not an anemone but related to mushrooms. Some say they're harmless, but I have over 20 (not pink, but clear) that multiplied from one and they bug my zoas.