Second part of my thinly veiled excuse to research X-men and call it work. The first post can be found here. This is only meant to be a two-parter but I'll see how I feel on Monday, and whether I can find any more X-men that are as amazing as bacteria.
4) Multiple Man
Multiple Man's power is that he can replicate himself, splitting his body into two or more identical copies in clear violation of the laws of conservation of mass. When he wants to get rid of these extra bits he can sort of return them to his body, reforming as one person. It's strongly suggested that he remains in control of all the extra multiple men as well, one of them can't go off and (say) rob a bank without him controlling it.
The bacteria: E. coli
[Edited due to serious reading comprehension error!]
Bacteria are the masters of dividing quickly and unlike multiple man, they aren't constrained by how many copies they can produce. E, colis is one of the fastest dividing bacteria in the world, splitting into two once every 15-20 minutes. While this might be slower than multiple man can manage, the end results are far more spectacular:
For those that can't get the sound, that's five thousand billion billion bacteria produced in one day, just from a single dividing cell. (link to video on youtube)
Berzerker is one of the lesser known X-men having appeared in only one of the comics. He did, however, make it onto two of the animated series (X-men: Evolution, the one where everyone is a teenager, and Wolverine and the X-men, which I've never seen). His power involves the manipulation of electrical energy; he can throw balls of electricity at people, convert his body into raw electricity, and change the channels on the TV without needing a remote.
The bacteria: Geobacter
I covered the amazing powers of Geobacter in my first ever post on this blog, but it's well worth reiterating because they are awesome. Geobacter might not be able to shoot balls of lightning at people, but they can certainly run a current through themselves, and more excitingly, they can run an electrical current up through a whole column of bacteria, essentially converting a chain of bacteria into a piece of electrical wiring.
The electrons are needed for the redox reactions that all organisms need to carry out to survive. By picking up electrons from the mud, and then transferring them up through pili to the surface the bacteria create an electrical current. You can read more about it on the old post.
Raven Darkholme, aka Mystique. In the film she's naked and blue with strategically placed scales. In the comics she's still blue but wears a little black two-piece for dignity. Head (or second in command depending on what universe you're in) of the brotherhood of evil mutants, her power is the ability to change form, to shape-shift into the features of another person.
The microorganism: Trypanosoma Brucei
I've cheated here a little. T. brucei isn't actually a bacteria, instead it's a single-celled protist, one of those organisms which are two large and structured to be a bacterium, but too weird to properly be a eukaryote.
T. brucei causes sleeping sickness, and has a fairly complex lifecycle involving humans and tsetse flies. Once inside the human it travels around in the blood, and can occasionally make its home inside various organs. Floating around in the bloodstream, however, is dangerous as it won't be long before part of the human immune system will recognise the intruder and start to rally a force to attack it.
The T. brucei deals with this by periodically changing its skin. Like Mystique, it can change form so that by the time the immune system gets back all ready to attack the recognisable intruder the intruder is no longer recognisable. The outer surface of the T. brucei is covered with a molecule called VSG (variable surface glycoprotein) and the T. brucei genome contains the information for an entire archive of VSGs, with only one being expressed at any one time. By switching to a new VSG, the T. brucei can remain hidden inside the body, constantly changing form and escaping capture.
Source for T. brucei picture.