The shrinking recipe is a quest item used during the Grim Tales quest. It is obtained by playing a special tune on the piano in the basement of the witch's house in Taverley. Playing the correct tune reveals a secret compartment in the piano which contains the recipe, a to-do list and 2 shrunk ogleroot.
The recipe requires a tarromin to be added to a vial of water followed by a shrunk ogleroot to make a shrink-me-quick potion. The potion can then be consumed by the player to allow them to enter a mouse hole in the witch's house to retrieve Miazrqa's pendant from a mouse that stole it from Miazrqa.
1x leaf of tarromin,
1x shrunken ogleroot.
Mix the tarromin in a vial of water, then add the shrunken ogleroot. Drink when standing in an area prepared with glyphs for this potion to have full effect. Take one dose only, for a new perspective on the world...