Mystery of the morning

[Trabby]

So as I'm observing my 90g reef in the dark this morning I noticed that a few things got rearranged overnight.... Mainly a couple of zoas that were not affixed to anything. No big deal this happens from time to time... Then I notice that a chunk of rubble about 2x2 is moved... Something is missing... So after looking closer I see that one of my zoa colonys are gone!! So on come the actinics and I'm looking for where they ended up... This is where it gets weird... I found them somehow pulled into a little cave area in the rockwork.. So basically the rubble chunk was pushed out onto sandbed... And the zoas that were next to it pulled in and under the rock..

A- I'm not sure I can pull them out without dismantling the left side of the rocks
B- I'm scared there might be a monster in there :s

my immediate thoughts are do I have something nasty lurking in there trying to lure me with my zoas? Does anybody have any thoughts.....