Description: The Small Heart of the Giant is a mystical gemstone that, when attuned, replaces the user's heart, intertwining with their very essence. This small, pulsating crystal takes the shape of a heart, shimmering with an otherworldly glow. Once attuned, the bearer's physical form becomes a vessel for the heart's powerful magic, granting them extraordinary abilities.

Abilities:

1. Alteration of Size: The attuned creature can command the Heart to alter its size without the need for a spoken command word. At will, the bearer can grow or shrink in size, with the limits set only by their imagination and the item's magic.

2. Enhanced Physical Attributes: When the user chooses to grow in size, their strength, constitution, and durability increase significantly. This results in a permanent +4 bonus to Strength, a +2 bonus to Constitution, and an increase in hit points equal to their character level times 5. Conversely, when shrinking in size, they gain a +4 bonus to Dexterity and a +2 bonus to Intelligence as they become more agile and attuned to their surroundings.

3. Perfect Fusion: The Heart integrates seamlessly with the user's body, making it impervious to removal or theft. The user can dismiss the visual appearance of the Heartstone, making it appear as if they have a normal heart to casual observers.

Drawbacks:

1. Symbiotic Bond: The user's life force is now intertwined with the Heart. If the gem is ever destroyed or dispelled, it will result in the immediate death of the attuned creature.

2. Mystical Dependency: The user becomes dependent on the Heart's magic to sustain their altered form. Without the Heart, the user gradually reverts to their original size over the course of 24 hours, losing the enhanced attributes gained through its magic.

3. Unstable Transformation: The process of changing size can be mentally and physically taxing. Each transformation inflicts a level of exhaustion on the user, and they cannot maintain an altered size for more than 1 hour at a time without incurring additional exhaustion.

4. Exhaustion: Each use of the Small Heart of the Giant's size manipulation ability comes at a cost. After returning to their original size, the attuned individual gains one level of exhaustion. Subsequent uses of the ability without completing a long rest increase the exhaustion level accordingly.(only applies to non-constructs)

Notes: Bonus: Strength Score, Bonus: Constitution Score, Size: Gargantuan, Size: Huge, Size: Large, Bonus: Dexterity Score, Size: Small, Size: Tiny, Size: Medium, Bonus: Intelligence Score