It seems that shooting up in the air with a machine gun clears people out of an area faster than telling them there is a sharktopus on the loose.
Duh. It's pretty hard to believe something so ridiculous unless you saw it for yourself.
Conan O'Brien's death in the sequel. He is impaled through the back by one of Sharktopus' tentacles, the end of it sticking out of his mouth. His head is then bitten off and chunked over towards some volley ball players, who use it as a volleyball.