While working on my tank I accidentally knocked my urchin off the side, and as luck would have it the urchin landed smack in the middle of the anemone. Removal off the urchin proved futile. Everything that touched the anemones stuck to the anemone like glue. Absolutely nothing I could do, so I decided to hope for the best. Seemed completely plausible that I might loose both the anemone and the urchin, at the very least one of the inverts would meet it's end. The Haddoni anemone completely enveloped the urchin for about 10 minutes and then expelled the urchin intact. The urchin lost some spines but 4 days later the urchin seems back to normal.