Hey guys! This is second tutorial. It is perfect for trolling
Step 1: Make a 1x2x2 cube out of any block
Step 2: Look on Pic 2. I can't explain this part.
Step 3: Make a funnel-like shape on the top. Look on Pic 3
Step 4: Get a bunch of Spawn eggs of the mob that you want. Make sure they aren't Chickens, Slimes, Magma Cubes, Creepers, Spiders, or Cave Spiders
Step 5: Spam right click on the top of the funnel. Look on Pic 6
Step 6: Block the funnel.
Step 7: Break the blocks that are blocking the cannon in Pic 2.
Step 8: Let it rip!
(Optional Step: Build it in the air and make it look like a gun)