Brain Coral

From the National Ocean Service:

Views from the seafloor! In this image, a close-up of brain coral is captured by a remotely operated vehicle (ROV). Scientists use the ROV to confirm the type of seafloor cover—from sandy bottom to hard coral.
See more images here from NOAA's Caribbean coral reef mapping mission: 

http://oceanservice.noaa.gov/caribbean-mapping/gallery-seafloor.html #ScienceAtSea