hulk uhlk hluk lhuk ulhk luhk hukl uhkl hkul khul ukhl kuhl hlku lhku hklu khlu lkhu klhu ulkh lukh uklh kulh lkuh kluh
Note: these 'words' (valid or invalid) are all the permutations of the word hulk. These words are obtained by scrambling the letters in hulk.