>>54316942>neither do any of thosebug - its an invertebrate, pokemon like shelmet and forretress are bug type
rock - mineral based shell makes up the majority of the pokemon
poison - slowbro/king mention how the shellder's poison acts on them
dark - tricky malicious nature
steel - the inner shell and spike appear to be metalic
ice - huh... well... hmm... gen 1 was lacking ice types and some oyster dishes are served on ice