Right now the one I have left is hosting a hole in a rock... that is kind of weird if you ask me... but over the years I have had them host bubble coral, frogspawn, torch, toadstools, devils hand leather, crowning toadstools, and various anemone like coralimorphs (shrooms and ricordias). It took them a number of months to host in a bubble tip anemone when I put that in the tank, but once they did they like that a lot and would not leave it alone until it came out of the tank. They hosted a lot of different pieces of equipment over the years too... really hard to make a call on what was the wierdest one..