Related Clues:

• Bio 101 subject
• Single-celled blob
• Bit of negative campaigning
• One that lives in a single cell?
• Ugly kind of campaign
• Campaign ugliness
• Blob
• Biology 101 subject (Var.)
• Tiny organism (Var.)
• Stain or smudge
• One-celled protozoan (Var.)
• Slide subject
• Organism on a slide
• Staple of political dirty tricks
• Campaign staple