Fall Through Slime Mod (1.21.8, 1.20.1) – Minecraft Slime Blocks Turn Semi-Solid

Fall Through Slime Mod (1.21.8, 1.20.1) introduces a quirky and unexpected twist to Minecraft’s slime block mechanics. Instead of acting as stable, bouncy platforms, slime blocks now behave like semi-solid surfaces when you’re standing still. Remain idle on one too long, and you’ll slowly sink into it transforming them into soft, gooey traps rather than static building materials.

This lightweight mod keeps all other slime behaviors intact such as bouncing and jump interactions but adds a sense of instability that can completely change how players build and explore. Whether you’re creating puzzle maps, parkour courses, or tricky redstone contraptions, this mechanic adds an element of risk and realism to slime usage.

Features:

• Slow Sinking Mechanic
  When players stand still on a slime block, they will gradually fall through it. Movement stops the effect, so it only triggers while idle.
• Unchanged Jump & Bounce Physics
  Jumping and bouncing on slime blocks still works exactly as in vanilla Minecraft. Only idle standing triggers the sinking behavior.
• Enhances Slime-Based Builds
  Makes slime structures feel unstable and squishy perfect for traps, mini-games, or immersive dungeon environments.
• Zero Configuration Needed
  The mod is plug-and-play. Simply install it on a compatible loader and the new behavior takes effect immediately.
• Compatible with Vanilla Mechanics
  Fully integrates with existing slime block logic no interference with redstone, pistons, or custom map setups.

Screenshots:

Requires:

Minecraft Forge

Collective Lib

How to install:

How To Download & Install Mods with Minecraft Forge

How To Download & Install Fabric Mods

Why use Fall Through Slime Mod?

This mod is great for builders, mapmakers, and server hosts who want to spice up player interaction with slime blocks. The passive sinking mechanic introduces tension and unpredictability, making slime structures feel more organic and alive. Whether you’re designing a squishy dungeon floor or a deceptive trap in a PvP arena, Fall Through Slime adds a fun layer of movement-based gameplay without overcomplicating mechanics or requiring extra setup.