Octopus

I remember when I first started out as a dive guide and being told that a particular dive site was great for spotting octopus.  After a while I began to get better at making dives more enjoyable by pointing out interesting things to see.  One thing to keep an eye out for are holes and crevices with rocks and boulders piled up at the entrance.  This often indicates that there is an octopus (or two) resident.  If the octopus wasn't disturbed too much he could generally be expected to be found in the same place on the next dive.

 

When threatened  an octopus's main defence is to hide.  They retreat into the space using their tentacles to pull back the rocks and protect itself.  They really are intelligent and you can almost sense their bewilderment in their eyes as you admire their home.  The most common secondary defence is to escape fast.  Other defence strategies I have seen includes squirting their ink and camouflaging. 

Be careful not disturb the Octopus too much or you might have your camera stolen.