Wondrous item, legendary

This item first appears to be a Large sealed iron barrel weighing 500 pounds. The barrel has a hidden catch, which can be found with a successful DC 20 Intelligence (Investigation) check. Releasing the catch unlocks a hatch at one end of the barrel, allowing two Medium or smaller creatures to crawl inside. Ten levers are set in a row at the far end, each in a neutral position, able to move either up or down. When certain levers are used, the apparatus transforms to resemble a giant lobster.

The apparatus of the Crab is a Large object with the following statistics:
Armor Class: 20
Hit Points: 200
Speed: 30 ft., swim 30 ft. (or 0 ft. for both if the legs and tail aren’t extended)
Damage Immunities: poison, psychic

To be used as a vehicle, the apparatus requires one pilot. While the apparatus’s hatch is closed, the compartment is airtight and watertight. The compartment holds enough air for 10 hours of breathing, divided by the number of breathing creatures inside.

The apparatus floats on water. It can also go underwater to a depth of 900 feet. Below that, the vehicle takes 2d6 bludgeoning damage per minute from pressure.

A creature in the compartment can use an action to move as many as two of the apparatus’s levers up or down. After each use, a lever goes back to its neutral position. Each lever, from left to right, functions as shown in the Apparatus of the Crab Levers table.
Apparatus of the Crab Levers (table)

Armor (light, medium, or heavy), rare (+1), very rare (+2), or legendary (+3)

You have a bonus to AC while wearing this armor. The bonus is determined by its rarity.

Armor (plate), legendary (requires attunement)

You have resistance to nonmagical damage while you wear this armor. Additionally, you can use an action to make yourself immune to nonmagical damage for 10 minutes or until you are no longer wearing the armor. Once this special action is used, it can’t be used again until the next dawn.

Armor (light, medium, or heavy), rare (requires attunement)

You have resistance to one type of damage while you wear this armor. The GM chooses the type or determines it randomly from the options below.

Armor (plate), rare (requires attunement)

While wearing this armor, you have resistance to one of the following damage types: bludgeoning, piercing, or slashing. The GM chooses the type or determines it randomly.
Curse. This armor is cursed, a fact that is revealed only when an identify spell is cast on the armor or you attune to it. Attuning to the armor curses you until you are targeted by the remove curse spell or similar magic; removing the armor fails to end the curse. While cursed, you have vulnerability to two of the three damage types associated with the armor (not the one to which it grants resistance).

Armor (shield), rare (requires attunement)

You gain a +2 bonus to AC against ranged attacks while you wield this shield. This bonus is in addition to the shield’s normal bonus to AC. In addition, whenever an attacker makes a ranged attack against a target within 5 feet of you, you can use your reaction to become the target of the attack instead.

Weapon (arrow), very rare

An arrow of slaying is a magic weapon meant to slay a particular kind of creature. Some are more focused than others; for example, there are both arrows of dragon slaying and arrows of blue dragon slaying. If a creature belonging to the type, race, or group associated with an arrow of slaying takes damage from the arrow, the creature must make a DC 17 Constitution saving throw, taking an extra 6d10 piercing damage on a failed save, or half as much extra damage on a successful one.

Once an arrow of slaying deals its extra damage to a creature, it becomes a nonmagical arrow.

Other types of magic ammunition of this kind exist, such as bolts of slaying meant for a crossbow, though arrows are most common.

Wondrous item, very rare

This bag superficially resembles a bag of holding but is a feeding orifice for a gigantic extradimensional creature. Turning the bag inside out closes the orifice.

The extradimensional creature attached to the bag can sense whatever is placed inside the bag. Animal or vegetable matter placed wholly in the bag is devoured and lost forever. When part of a living creature is placed in the bag, as happens when someone reaches inside it, there is a 50 percent chance that the creature is pulled inside the bag. A creature inside the bag can use its action to try to escape with a successful DC 15 Strength check. Another creature can use its action to reach into the bag to pull a creature out, doing so with a successful DC 20 Strength check (provided it isn’t pulled inside the bag first). Any creature that starts its turn inside the bag is devoured, its body destroyed.

Inanimate objects can be stored in the bag, which can hold a cubic foot of such material. However, once each day, the bag swallows any objects inside it and spits them out into another plane of existence. The GM determines the time and plane.

If the bag is pierced or torn, it is destroyed, and anything contained within it is transported to a random location on the Astral Plane.

Wondrous item, uncommon

This bag has an interior space considerably larger than its outside dimensions, roughly 2 feet in diameter at the mouth and 4 feet deep. The bag can hold up to 500 pounds, not exceeding a volume of 64 cubic feet. The bag weighs 15 pounds, regardless of its contents. Retrieving an item from the bag requires an action.

If the bag is overloaded, pierced, or torn, it ruptures and is destroyed, and its contents are scattered in the Astral Plane. If the bag is turned inside out, its contents spill forth, unharmed, but the bag must be put right before it can be used again. Breathing creatures inside the bag can survive up to a number of minutes equal to 10 divided by the number of creatures (minimum 1 minute), after which time they begin to suffocate.

Placing a bag of holding inside an extradimensional space created by a handy haversack, portable hole, or similar item instantly destroys both items and opens a gate to the Astral Plane. The gate originates where the one item was placed inside the other. Any creature within 10 feet of the gate is sucked through it to a random location on the Astral Plane. The gate then closes. The gate is one-way only and can’t be reopened.

Wondrous item, rare

This small black sphere measures 3/4 of an inch in diameter and weighs an ounce. Typically, 1d4 + 4 beads of force are found together.

You can use an action to throw the bead up to 60 feet. The bead explodes on impact and is destroyed. Each creature within a 10-foot radius of where the bead landed must succeed on a DC 15 Dexterity saving throw or take 5d4 force damage. A sphere of transparent force then encloses the area for 1 minute. Any creature that failed the save and is completely within the area is trapped inside this sphere. Creatures that succeeded on the save, or are partially within the area, are pushed away from the center of the sphere until they are no longer inside it. Only breathable air can pass through the sphere’s wall. No attack or other effect can.

An enclosed creature can use its action to push against the sphere’s wall, moving the sphere up to half the creature’s walking speed. The sphere can be picked up, and its magic causes it to weigh only 1 pound, regardless of the weight of creatures inside.