The Glittering Grotto is a magical cave located in Ponyland in the G1 comic books.
The entrance is very small, small enough that an adult pony has to crawl to enter the grotto. Brightly colored pebbles, moonstones, and shiny flowers are scattered around the interior of the cave.
However, trying to remove them from the cave can be dangerous. When some of the ponies went hunting for a trinket for Sparkler, their bodies started to deform when they left the grotto, with one pony shrinking down to the size of a mouse and three other ponies growing to enormous (but disproportionate) proportions. When the ponies kicked the pebbles they had picked up back into the cave, they went back to normal.
The Glittering Grotto then disappeared completely, leaving only a shiny patch of grass where it used to be.
- In My Little Pony #23, the ponies and wind wavers go there to try to find a pebble mouse for Sparkler, to replace the one she lost.
- "Sparkler's Special Friend." My Little Pony #23, London Editions Ltd. July 17, 1986.