Break the Lucky Crystal Block and anything could happen frogs rain down, lightning strikes, you get free tools, or a Creeper appears! This is your capstone project you've learned everything you need.
The Lucky Crystal Block is a special block that overrides the onBreak() method. When a player breaks it, instead of just dropping items, it picks one of 5 random events. Each event is a case in a switch statement.
world.getRandom().nextInt(5) which returns a number 0, 1, 2, 3, or 4 — each with equal probability. Each number triggers one event.
Create LuckyCrystalBlock.java. It extends Block and overrides onBreak(). When broken, it picks a random number 0–4 and runs the matching event. All the good stuff happens in this one file!
Right-click the crystalmod package → New → Java Class → LuckyCrystalBlock
!world.isClient()? Minecraft runs game logic twice once on the server (real logic) and once on the client (prediction). We cast to ServerWorld to access server-only methods like entity spawning. Always guard world-changing code with this check!
!world.isClient() guard is essential. Without it, all 5 events fire twice — once on the server and once on the client causing double entity spawns and chaos. Students often remove it thinking it's unnecessary. Also: onBreak fires as the block is being broken, before it's fully removed calling super.onBreak() first is required.new LuckyCrystalBlock(...), not new Block(...). The onBreak override only exists on your custom class.if (!world.isClient()) guard. Add it back wrapping the switch statement.!isClient(). If IntelliJ warns, you can add @SuppressWarnings("unchecked") above the line.} but after the closing } of onBreak).Add the eventFrogRain method to LuckyCrystalBlock.java. It spawns 5 Crystal Frogs at slightly random positions around the block.
+ 2 on Y spawns them a bit above the block so they fall down!
Drop 16 Crystal Gems as item entities at the block's position. Item entities are the spinning items you see floating on the ground they use ItemEntity.
new ItemStack(item, count) creates a stack of items. The setVelocity call makes the gem stack fly up and scatter sideways — just like when a creeper explodes near chests!
Summon a LightningBoltEntity at the block location. This is a real lightning bolt it'll set fire to things, transform mobs (pigs into piglins!), and make a big flash.
lightning.setCosmetic(true); before spawning it.
EntityType from net.minecraft.entity.EntityType to get the LIGHTNING_BOLT type. IntelliJ will offer to add it automatically just press Alt+Enter on the red squiggle!
Directly give items to the player's inventory using player.getInventory().insertStack(). This is a reward event if you're lucky enough to roll this, you get free tools!
insertStack() puts the item in the first available inventory slot. If the inventory is full, the item goes on the ground instead. You could also use giveItemStack() which does the same thing.
The "bad luck" event spawn a fully charged Creeper right next to the player. This is the risky event that makes the Lucky Block exciting!
creeper.setFuseSpeed(1); before spawning this makes it start the fuse countdown immediately!
Open ModBlocks.java and add the Lucky Crystal Block. It glows (luminance 15 max!) and is a bit harder to mine than the Crystal Block. We want it to feel special.
Add the Lucky Crystal Block item to the creative tab. Open ModItems.java and update registerModItems():
The Lucky Crystal Block needs the same set of files as the Crystal Block from Episode 2: a blockstate, two model files, a texture, and a loot table. We'll skip the loot table this time the block's special events ARE the loot!
Create assets/crystalmod/textures/block/lucky_crystal_block.png a 16×16 pixel image. Make it look special try a vivid pink/purple with a star or "?" pattern on it!
"pools": [] means the block drops nothing. The onBreak events handle what the player gets we don't want both a loot drop AND event rewards!
The Lucky Crystal Block is crafted from 8 Crystal Blocks surrounding one Crystal Gem an expensive recipe that matches how rare and powerful it should be!
"minecraft:crafting_shapeless" and use "ingredients" instead of "pattern".
Just like in Episode 2, blocks need to be in the mineable/pickaxe tag to be properly mined with a pickaxe. Open the existing pickaxe tag and add the new block.
Open data/minecraft/tags/block/mineable/pickaxe.json and add the new block:
"replace": false means we ADD to the vanilla list rather than replacing it.
Build the mod and test every event. On average you'll need to break ~10 Lucky Crystal Blocks to see all 5 events. Use /gamemode creative to get infinite blocks!
LuckyCrystalBlock (not just Block) in ModBlocks.java. The custom class is what adds the onBreak override!
/gamemode creative so you can place and break blocks infinitely. You can also temporarily change nextInt(5) to nextInt(1) to always trigger the same event while testing!