There is two ways of obtaining this trophy, first of all, in the level Hi-Ho Moskito during the first unlocked area Jibberish Jungle, you can suck in missles and fire them back at the Hunter. It does take two hits to kill the Hunter. Secondly, if that method doesn't work for you, in Ticklish Temples the level called Outta My Way there are Hunter there, swim underneath the platform he's on, jump up behind him, and he won't turn around. From there, the missle will shoot around, avoid it, and enjoy your trophy!