Brooch of Many Sizes (Patreon)

Wondrous item, rare

This metal brooch can be used to secure a cape or pinned to adorn a piece of clothing and features a rotatable dial. As an action, a willing creature wearing the brooch can cast the enlarge/reduce spell on itself by turning the dial toward either the larger or smaller figure adorning the sides of the brooch. Once this ability has been used, it can't be used again until the following dawn.

The creature can choose to overload the brooch as a bonus action once the spell has been cast by forcibly twisting the dial beyond its normal limits. When it does, the creature's size changes by an additional category: growing either a second size larger if it had cast the enlarge spell or a second size smaller if it had cast the reduce spell beforehand. The creature's size can't be larger than Huge or smaller than Tiny in this way, and its damage and weight is increased or decreased as if it were affected by a second instance of the enlarge/reduce spell.

When a creature returns to its original size after overloading the brooch, it can't move or take actions until after its next turn. Once the brooch has been overloaded, it can't be use again until 7 days have passed.

He reached to his chest, toward the pin he kept over his heart. They might underestimate the fury of a gnome, but not the fury of one that stood as tall as they did.