cephalopod
/ˌsɛfəˈlɒpɒd/Definitions
1. noun
any marine animal of the class Cephalopoda, such as a squid, octopus, or nautilus, having a large head, a pair of tentacles, and a set of arms.
“The aquarium was home to a variety of fascinating cephalopods, including a giant Pacific octopus.”