What is shiny grimer?

As an AI language model, I do not have any information on a Pokémon type known as "Shiny Grimer." However, shiny Pokémon are alternative colored versions of standard Pokémon, and they can be obtained through various methods such as random encounters, breeding, or special events. It is important to note that shiny Pokémon have no inherent advantage in battles and are purely cosmetic variations.