Evolving
Evolving
[Bacterial cell culture.] What? Staphylococcus aureus is evolving!
...
Off-screen: Aww, crap. Staphylococcus aureus evolved into Methicillin-resistant Staphylococcus aureus!

In a Pokémon game, a player goes out in search for the eponymous creatures. Many Pokémon can be found directly in the wild, but there are also a lot of Pokémon that require training and growth, to cause them to "evolve" into new Pokémon. "Evolve," the game's term, is a misnomer which earned itself quite some controversy in the past; in reality, Pokémon "evolution" is more akin to puberty or metamorphosis, since instead of the entire species of Pokémon acquiring changes through an extended period of time, one specific member of the species grows instantly to the "higher stage." At that point in the game, the Pokémon glows before transforming into the new form, then stops glowing, and the very same text "What? XXX is evolving!" is used (see this video or those screenshots for instance). The changes of such a transformation can be quite dramatic ... or not.
This comic depicts the "evolution" of bacteria as observed by a Biologist in the same format as the game Pokémon. Here we have Staphylococcus aureus , which is not a desirable bacterium (it causes Staph infections ) which evolves into "Methicillin-resistant Staphylococcus aureus " . Methicillin is an antibiotic. If the bacterium becomes resistant, it means the antibiotic will be less effective against it, making infections harder to treat. Thus the observer is not pleased with such an evolution.
The title text references this by suggesting that biologists do not want bacteria to evolve in this way, as opposed to Pokémon where you put a Pokémon on the "front lines" as much as possible to gain it experience and hope it evolves. A point of irony is that Pokémon evolution can easily be prevented, by using an Everstone, or stopped, by pressing the B button in the game controller during evolution, especially if there are Pokémon that one does not want to evolve. The bit about the front lines is that, if a bacteria colony is exposed sufficiently to an antibiotic, those bacteria with any level of resistance to the antibiotic are less likely to be killed by the antibiotic, and are able to reproduce in spite of the antibiotic. Most future generations of bacteria now have this level of resistance instead of just a small subset. This makes the likelihood of future more resistant and harder to treat mutations even more likely.
Staphylococcus aureus is a very common bacterium, that under an electron microscope looks like the xkcd drawing, and is the major cause of staph infections in the nostrils and skin. Hospitals are often plagued with outbreaks of Methicillin-resistant Staphylococcus aureus (MRSA), which is very difficult to treat as the typical antibiotics do not work on it.
[Bacterial cell culture.] What? Staphylococcus aureus is evolving!
...
Off-screen: Aww, crap. Staphylococcus aureus evolved into Methicillin-resistant Staphylococcus aureus!
