Historical clue formulations

• Creatures named for their changing shape — 2021-10-14
• Amorphous creatures — 2020-02-16
• Ones moving with the aid of pseudopods — 2018-03-18
• Shape shifters? — 2013-10-18
• Little blobs on slides — 2012-02-21
• Shape shifters? — 2009-06-20
• They haven't any definite forms — 2005-11-13
• Pseudopod formers — 1999-02-21
• Microscope slide subjects — 1996-08-21