Mob Prank

You will meed these materials
 * A Dispenser
 * A Pressure plate (to make it to look like its invisible, use a stone pressure plate)
 * 6 or more pieces of redstone dust.
 * 9 to 576 arrows

Step 1
First dig down 2 squares in a shape stairs and then Dig back up in the shape of stairs.

Step 2
Go 2 blocks and on the 2nd block, put the dispenser.

Step 3
On the stair shaped Blocks, put redstone including in front of the dispenser

Step 4
Put the Pressure plate at the end of he redstone line

Step 6 (Drumroll Please!)
Lure any mob to the pressure plate and they get hit (They will survive but it's worth it, and if you have 11w49a you don't have to lure a mob)

(Please change the name to Mob Prank)