Lime Cushion

Lime Cushion is a placeable entity that a player can sit on, crafted from three wool slabs of the matching color. It settles on top of almost any block in the world — excluding fluids and a small set of blocks with no real surface — and breaks a short time after the block underneath it is removed.

Because Lime Cushion is an entity rather than a block, it cannot be mined with a tool: it breaks the instant it is attacked, whether by a player, a projectile, or another entity, even if no damage would otherwise be dealt, and it also breaks if left sitting in lava. Java Edition and Bedrock Edition disagree on pistons — in Java Edition a piston that tries to move Lime Cushion breaks it, while in Bedrock Edition a piston can push it along.

Sitting on Lime Cushion shields a player from knockback, geysers, portals, and piston movement until they get up again, and unlike wool-based blocks it does not dampen vibrations picked up by a sculk sensor. It can also be used as furnace fuel and recolored with a matching dye, and it generates naturally near campfires in abandoned camps.