A leviathan monster from the Monster Hunter series.
Known as the Lord of the Seas, the Lagiacrus is a species of large, blue, aquatic monster that dwell in the sea and large bodies of fresh water. It's capable of generating electricity through the dermal spikes on it's back and unleashing it in the form of devastating Thunder attacks. It's also known to come onto dry land to sunbathe and rest. While most at home in the sea, it's more than capable of defending itself on land.
Lagiacrus is the flagship monster of Monster Hunter 3, where it was first introduced. Despite this, it did not appear in Monster Hunter Portable 3rd. It is, however, set to reappear in Monster Hunter 3 G, in addition to a white subspecies.