For a side project I decided to make characters from the super mario brothers universe somewhat realistic/comic bookish and give them backgrounds and stories that make sense. For example..why are goomba's evil, why are they called mushroom people?
here is the first round of enemies.
Buzzy Beetle: A beetle that is found in dark areas. Given its name due to the almost deafening buzzing sound it makes, It is roughly 4 feet in hight and feeds on goombas and pretty much any thing else it can find. It is a scavenger. If it gets scared it pops into its shell. Buzzy Beetles can not be harmed with fire power, and despite the look of its body, Buzzy Beetle is very fragile without its shell, often times Mario is able to stomp the head, dump the body and use the shell as a weapon.
Bullet Bill and Bill Blaster: Bill Blaster Cannons are placed sporadically throughout the mushroom kingdom by bowser and his minions. Bullet bills come from an underground source through the tube constantly keeping the blaster cannons loaded. It is thought that the bills have a living being in them, however it is unknown if this is the case. Those who have seen bullet bills say that it may also be a mechanical being created by Jugem Lakitu. The Bullet Bill is extremely dangerous, able to change direction almost instantly and explodes on contact.
Chain Chomp: These curious creatures are watchdogs often found near Bowser's many fortresses and castles. The bouncing of the springs that allow them to "bite" make a rough barking sound. It is unknown whether these beings are mechanical or have sentience to it. It is however very dangerous if someone gets too close. Its "teeth" are as sharp as razors. Generally they can only go as far as their chain allows them, however sometimes these creatures are able to break free. There is currently no known way to stop them other than avoiding them.
Piranha Plants: These weed like creatures tend to form around the sewer systems and pipes in the mushroom kingdom and surrounding areas. During the summer they are a plentiful nuisance often snatching up mushroom kingdom citizens, Monty Moles and other small things that come within their grasp. There are a few different types of Piranha plants, all of them just as deadly with very sharp teeth. They are a relative of the venus flytrap, the difference being that they attack as opposed to waiting for prey.
Some plants are able to produce fire on rare occasions and they can grow to be 8 feet tall with the bulb (or head) weighing 150 lbs. These are very dangerous plants who should be avoided at all costs.
Buzzy Beetle and the Piranha Plant are not minions of bowser, simply antagonists of the mushroom kingdom who happen to inadvertently help with stopping Mario.
This is the case with many of the "enemies" of Mario, being that the land is filled with dangerous animals.