This is five ways to troll in minecraft

One- Put tnt under their door pressure plate
Two- Take their crafting table
Three- Spawn a ton of creepers in their house and use invisible potions on them
Four- Put bedrock around their house
Five- When they go into cave block off entrance with lava waterfall

I know its short but I needed some quick xp to level up, diamond or subscribe If you want to. 

---