What are some examples for pleomorphic bacteria?

Hint: Bacteria were first discovered by Antony Van Leeuwenhoek in 1676 in ponds and tartar scraped from teeth. He called them animalcules because of their motility and small size. The average size of bacteria is 2.0-2.6µm. The smallest bacterium is Dialister pneumosintes which measures 0.15-0.30µm and the largest bacteria is 500µm long and belongs to Spirochaete.

Complete answer:
The bacteria which are present in different shapes and forms like curved, club-shaped, filamentous, coccoid because of the absence of cell walls and the plasma membrane forms the cell outermost boundary and showed pleomorphism. The cell wall is not present, so these are able to change their shapes and forms and are called pleomorphic bacteria.
Examples of pleomorphic bacteria –
Mycoplasma is present in different forms and shapes. They have a plasma membrane which is rich in lipoglycan and sterols. They lack cell walls which can make them capable of changing their shapes according to the environment. It belongs to the genus Monera which includes all prokaryotic organisms.
Corynebacterium is an aerobic and Gram-positive bacteria. They have the following shapes like bacilli, club-shaped, by having the genus name Coryneform means club-shaped.
Helicobacter pylori also comes under the pleomorphic bacteria and are present in different forms like curved rod and a coccoid form.
Deinococcus radiodurans is a radiation-resistant bacterium and an extremophile.
Legionella pneumophila is also an example of pleomorphic bacteria.

Note-
Rickettsias also comes under the examples of pleomorphic bacteria because they have a smaller genome and have shapes like non-motile cocci or rod-shaped. They reproduce by the method binary fission (asexual reproduction). They cause various diseases in human beings such as scrub fever, typhus fever, rocky mountain spotted fever.