A Grotto spawner is an item that can be only obtained by spawning it in. It can be used to instantly spawn a Hidden Grotto around the player. This will only occur is the player is in Creative mode; if not, nothing will happen. The Grotto spawner shares its inventory sprite with the Old Rod.
On a Sponge server, the "pixelmon.grottospawner.use" permission node is required to use Grotto spawners.