Possible Clues:

• Invertebrate such as a snail
• Eg, a snail
• Shelled invertebrate
• Oyster or slug, eg
• Perhaps 05050 in the scum of its shell
• Sort of shellfish
• Creature with soft body and hard shell like snail
• Gangster's friend goes to American clubs for a slug, perhaps
• Clam or mussel, for example
• Invertebrate that often has shell