Ceiling Hover



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Ceiling Hover is a glitch that makes the player "hover" between a ceiling and a bouncy block (slime, or beds since 1.12). It can be performed by jumping under a ceiling such that the block 2.001b below the ceiling has bouncing properties.

Explanation
Whenever the player collides vertically with a block (floor or ceiling), the game will apply collision physics.

For almost every block, that just means setting the player's vertical speed to 0.

There is one exception: Slime Blocks (and Beds in 1.12+).


 * If the Player is sneaking, it's treated as a regular collision (Vertical motion is set to 0)
 * Otherwise, it checks if the player's speed is negative, then inverts it.

Note that nothing would happen if the player is somehow moving at a positive speed (and not sneaking).

In fact, that's exactly what happens with this glitch.

When the game detects a vertical collision, it will consider the block 0.2m under the player's position to apply collision physics (even for ceiling collisions...)

Let's review the steps for the 1.8125bc Ceiling Hover setup:
 * 1) Jumping under 1.8125bc applies vertical collision with the block 0.2m below the player (at ground level).
 * 2) If that block is a slime block, then vertical speed won't be set to 0, and the player remains suspended under the ceiling.
 * 3) Repeat step (2) until the player's vertical speed becomes negative due to gravity.

Note: This glitch happens for a few ticks, but with Jump Boost it would take longer. Ceiling hover can be interrupted at any time by sneaking.

Consequences
This glitch is pretty insignificant: it isn't game-breaking in any way, and requires very specific setups to be made use of.