One of my friends has only started playing about a month ago and we have started a Minecraft world together. He is picking it up very fast but I have a very evil plan. He will not know about my disc 11. We have a mining hub room where he goes afk a lot of the time looking at stuff on his phone but he's still there just not paying attention.
So my plan is to do a skeleton-creeper disc farm until I have disc 11. Hide a music box in the ceiling somewhere. Then when he's clearly there but AFK I will say I've got to go for 10 mins. Mute my mic but not actually go anywhere. Wait about 2 mins. Drink an invisibility potion. Start playing disc 11 and block off the entrance with obsidian. Go around knocking out all the torches one by one. He scares easily and he WILL BE FREAKING OUT AT THIS. Then just as it reaches the end and it sounds like a monster comes out, I will hit him once with my sword as to not kill him but just give even more of a scare.
It is quite an evil plan as like I said he scares easily. Any time he is mining and finds lava he screams. Any time a creeper surprises him he also screams.
But it will be hilarious. If my id is still visible above my head then sadly I won't be able to do most of it, all I can do is pretend I'm not there and just play disc 11 which will still freak him out having never heard it before. He will definitely think it's some scary monster he's never experienced before coming for him in Minecraft.