"Grimer's sludgy and rubbery body can be forced through any opening, however small it may be. This Pokémon enters sewer pipes to drink filthy wastewater."
While many Pokemon are logically based on something from the real world, others are a case of "What if?" For example, what if toxic sludge or waste became a living being? I present to you, Grimer. You almost have to wonder how this Pokemon came to be, and yet, it's totally believable. Grimer is seen in every generation via trainers, and even got an Alola form in the recent Sun and Moon games.
Grimer's Basic Attacks are Poison Jab and Mud Slap, while its Special Attacks are Mud Bomb, Sludge, and Sludge Bomb.