Assuming Mojang has figured out how to properly implement code for moving blocks that isn't infested with bugs, I think the timing can't get any more perfect than bringing back our beloved floatater with the introduction of the sift.

The ichor is clearly not designed to just be a pretty thing that damages you; it's also a valuable resource for the illagers when it comes to contraptions and magics. With this in mind, I don't think it's too far-fetched to expect vanilla ichor to also bring some value to players who come visit the sift. This alone should be a nice enough reward for anyone who is brave enough to face ancient city!

Ichor Pool

Scattered around the sift are ichor pools. Ichor is similar to lava in its viscosity - it cannot be made to run infinitely when put in a 2x2. But fret not, some pools contain this special block under them called "ichor spring." Ichor spring block cannot be picked up even with silktouch. This is to encourage players to venture out and settle a station of some sort spread across the dimension.

Its only special property is to renew a source block of ichor on top of it when the tide (time of day) is at Thrive, where souls regenerate faster. Since the ichor liquid has some soul texture scrolling over it, I think this is only appropriate.

Ichor can be scooped up using a bucket and put into a brewing stand to fill empty bottles with distilled ichor. You cannot pick up ichor straight to the bottle because I think it doesn't make sense that something that burns inside and out can be put into a glass bottle. Plus, with this system, you're forced to actually prepare you resources for the to be mentioned floatater fuel mechanic. And that brings me to....

Floatater

Of course, it's not going to be actually called that. But as you probably already know, floatater is a joke block from the poisonous potato dimension snapshot that pushed any block that sticks to its front as if they're moving entity; drifting indefinitely until a block is blocking the way.

It is powered by redstone, but a bottle of distilled ichor still has to be inserted into it. There's no UI - you simply right click it when holding a bottle. It displays 3 dots on the left and right sides of the block, you can track your fuel this way.

A bottle of distilled ichor can fuel a floatater 1 dot each, which is a travel distance of roughly 200 blocks. That makes a fully charged floatater to drift up to 600 blocks. I don't know if this is balanced or not, feel free to discuss it in the comment section.

Infused Sculk / Sift Cobalt

The mineral used for this "floatater" is native to the sift. The reason why I'm calling the ore blocks "infused sculk," instead of simply "blank ore" is because I want to follow the "gilded blackstone" naming convention. It's also named that way to stay faithful with the "terrain being made out of flesh of a living creature" theory people have been discussing.

The mineral itself is called Sift Cobalt, similar to how the nether has its own specific quartz instead of just generic quartz. I can imagine sift cobalt having its own block set too, adding incentive to its addition. But for now, it's just here to make the "floatater" recipe feel exclusive.

Wisp

Wisp (or Keeper Wisp) is a translucent flying passive mob that spawns upon a player's death. It holds a dead player's items up to 1 Inventory Row (9 separate stacks of items). Items held by Wisp can be retrieved by any players with a single right-click or a punch.

Spawning

Wisps spawn when a player with at least 1 XP Level died. A dead player can spawn up to 5 Wisps at a time if they had 5 Levels when dying; each Wisp costing 1 XP Level to be spawned.

Despite using Levels as the metric system, the actual amount of XP spent are exponential based on the XP Level formula, corresponding to the order of the Wisp's spawn.

• For example: The first Wisp spawn requires 7 XP value (not to be confused with Level), the second Wisp requires 16 XP value, the third Wisp requires 27 XP value, etc.

If a player has fewer than 5 Levels on death, Wisps only spawn as many as whole Levels the player had. Any remaining items and excess XP will drop on the floor.

• For example, if a player died with 2.5 XP Level, they can only spawn 2 Wisps, with the rest of the items and 0.5 XP dropped on the floor.

Wisps spawn in a set of order that determine which Inventory Row they're holding. Below is list of spawn order of Wisp and their inventory assignment:

• ‌1st Wisp: holds hotbar items
• 2nd Wisp: holds equipment and Off Hand items‌
• 3rd Wisp: holds bottom inventory row‌
• 4th Wisp: holds middle inventory row‌
• 5th Wisp: holds top inventory row

Despite being assigned with numbers internally, all 5 Wisps spawn simultaneously in the actual gameplay.

Naturally occurring Wisps only spawn in Survival and Hardcore mode. Although, with the latter, Wisps can only be meaningfully interacted with via Spectator Mode post-death, or by another player in the same Hardcore world.

Dying with XP in Creative and Adventure mode does not cause Wisps to spawn.

Appearance

Wisps spawn into either of the 3 colors variants depending on the number of slots they're holding.

• ‌Blue Wisp: holds 6–9 slots (+ 1 XP Level)
• Yellow Wisp: holds 1–5 slots (+ 1 XP Level) ‌
• Green Wisp: doesn't hold item (+ 1 XP Level)

An item-carrying Wisp (Blue and Yellow) displays the items being held within its translucent body. The displayed item cycles between the 1–9 slots, similar to a Trial Vault albeit with a slower pace.

Green Wisp only spawns when the Inventory Row it's assigned to is completely empty. For example, if a player died without any armor nor Off Hand slot equipped, the second Wisp will spawn as Green.

Retrieving Items

There are 2 methods of retrieving items from a Wisp: right-clicking for safe retrieval, and punching for quick retrieval.

A.) Safe Retrieval

Right-clicking an item-carrying (Blue or Yellow) Wisp must first be initiated with an eye contact. If successful, Wisp will put all the items it's holding straight to the player's inventory at once, similar to the powered Shelf behavior. At the same time, the Wisp will turn Green, indicating the only remaining thing it's carrying is EXP.

Retrieving items can be done even by player who didn't die and made the Wisps to spawn.

Right-clicking a Wisp when it's looking away doesn't do anything.

Right-clicking a Green Wisp (XP-only-carrying Wisp) doesn't do anything either.

B.) Quick Retrieval

Punching a Wisp – regardless of the tool in Main Hand – will instantly kill it, dropping all the held items and 1 Level's worth of EXP to the floor.

Drops

Upon death, Wisp drops all the items it was holding to the floor, including 1 Level's worth of XP. However, the actual XP value always corresponds to the Wisp's spawn order:

• First Wisp = drops 7 XP value
• Second Wisp = drops 16 XP value
• Third Wisp = drops 27 XP value, Etc.

A cumulative of 5 Wisps will always return a total of 5 Level worth of XP drop.

Green Wisp also drops 1 Level's worth of XP upon death; however, no items are dropped from it.

Behavior

Wisps always remember the death position of where their player died. They will not wander more than 8 blocks horizontally and 3 blocks vertically from the death position.

Wisps are capable of phasing through any block, including walls, lava, and water. They don't take damage in lava or fire, can't drown underwater, nor being slowed down by cobwebs. Despite this, Wisps generally prefers to linger in the open air.

Additional Notes

• "Safe retrieval with eye contact" mechanic is deliberately designed to be a bit cumbersome. This is to incentivize players to make an informed decision based on their environmental situation: "Should I take my time to face one Wisp at a time for safe retrieval? Or should I kill them all for an instant, but reckless item drops?"
• The reason why I made Wisps able to phase through blocks is to prevent them from suffocating; in case spawned in tight spaces. Which can lead to the deletion of the item they are carrying.
• In the vanilla game, 7 XP Levels are recoverable from death instead of just 5. Because of this, with the Wisp system, I'd make the remaining 2 XP Levels recoverable too by simply dropping on the ground instead of turning into Wisps. (I could just add 2 more Wisps, but that'd be asking too much to players for what supposed to be the helper/streamliner of recovery process, not to mention visual clutter.)
• I was debating on whether to raise the Wisp's spawning threshold to 3 EXP minimum, but I stumbled a lot on the XP/Level terminology and decided to stay with the current system so I can get my idea across clearly at the simplest form.
• I based off my Wisp design of Allay's early model with a mix of Dungeons Wisp. I hope the distinction is sufficient to make this mob able to stand on its own without leaning too heavily on a pre-established piece.
• Even though Wisp could already work perfectly as a mere safety net/progression checkpoint mob of Minecraft, they technically could be implemented as another means of holding loots in structures. I believe the map makers and world gen datapackers would love this creature for their own designed lore.
• I know some Hardcore players would feel like missing out on this cute mob if they were only naturally occurring by player's death. So I had an idea of adding potion of Keeping by brewing Sculk block. This potion would make any affected mobs [with loot drops] to spawn a Wisp on death. However, this is just another crude idea pitch that I had. I'm not sure how to balance this potion due to the ramification it would cause to the greater Minecraft gameplay loop. So I'll save this concept for a future idea.

Aaand that's it!

This is the first time I tried to write something in Minecraft wiki format, in formal English too no less. I hope I don't make some parts confusing with my poor wording/phrasing skill.

Other than that, I'd love to hear your thoughts about this idea I've been cooking up for a while now :]