The Leechgrave's main body is a decrepit, black coffin with pale gold lining. The coffin is surrounded by a large, silver chain, has two large, silver nails driven partway into it, and has a small hole near its top where a single, glowing yellow eye peers out. Occasionally, two large, pale green, clawed hands force their way out of the coffin, though no other part of the coffin's contents are visible. Its Heartless emblem, decorated by red patterns resembling claw marks, is located on the lower half of the coffin. The coffin hangs from a pink and red-violet bud with angular, pale yellow spirals for eyes. The bud sprouts four dark green, thorny roots that anchor the Leechgrave to the ground.
The roots are the source of the Tentaclaws, which act as the Leechgrave's appendages. Tentaclaws are black creatures lined by thorns, with red tips and three black mandibles, each with three curved spikes resembling scythe blades.
The Leechgrave's name references the casket-shape of its body and its cannibalistic behavior. By devouring other Heartless, it steals the hearts Organization XIII hopes to use, thus making it a leech or parasite to their goals. Its Japanese name, "Parasite Grave", is similar to another Heartless boss, the Parasite Cage (パラサイトケイジ). The Tentaclaw's name reflects its tentacle-like body and its clawed mandibles.
Kingdom Hearts 358/2 Days
After finishing a mission to exterminate a Carrier Ghost at Halloween Town, Roxas heads back to the castle. However, as he approaches the portal home, he is startled when a Tentaclaw suddenly bursts from the ground. He defeats the Tentaclaw and goes home, but a month later the Organization learns that all the Emblem Heartless have mysteriously disappeared from Halloween Town.
Roxas is sent to investigate, and discovers that Tentaclaws have overrun the town. He tracks them to their source, and finds the Leechgrave, which had been eating the other Heartless. After a battle, Roxas defeats the Leechgrave and releases its hear. Unbeknownst to Roxas, Jack observes him while brainstorming new scares. The combination of Roxas's cloak and the Leechgrave's tentacles inspires Jack to create the Scarecrow, which he presents to Dr. Finkelstein. as Roxas passes by on his way home.
The Leechgrave is a large Heartless rooted to the ground. To attack, it can swing the coffin at Roxas, open it up to slash at him with ghostly arms, fire poisonous pollen at him, or emit a poisonous mist. However, its main mode of attack is to use the Tentaclaws to batter and swallow Roxas.
Make sure to bring Cure/Cura magic and the Auto Life panel. A small stockpile of Fire spells are also a good idea for dealing with the Tentaclaws. The Leechgrave is vulnerable to critical hits.
The most efficient strategy is to remain amongst the Tentaclaws for as long as possible. Move close enough to the Leechgrave that it tries to attack with its ghostly hands, but make sure to move away before it does so in order to stay safe. Immediately after, the Leechgrave will pause for a short period—unleash at least one combo on it in that time. However, if it begins getting ready to use another attack, especially the poison mist or arm-slash, move away quickly. Though the Leechgrave itself is immune to magic, damaging spells are useful in eliminating the Tentaclaws.
After depleting the Leechgrave down to a health bar or two, begin taking out the Tentaclaws, using Fire spells and aerial combos. Leave one Tentaclaw to whittle away at Roxas's health until Roxas hits the Alarm Zone. Next, kill the Tentaclaw so that Roxas can immediately unleash a Limit Break on the Leechgrave when it staggers. Also note that in this battle only, the Tentaclaws will be stunned if their attacks are blocked, leaving them more vulnerable to attacks.
The Tentaclaws serve as the Leechgrave's weak point. When all four of the Tentaclaws guarding the Leechgrave are destroyed, the main body will fall over, leaving it open to attack. However, after recovering from its daze, all four Tentaclaws will regenerate.