Minecraft PE: Mob Rollarcoaster

Step 1:

Make a roller coaster track (any track works, and be sure to add powerails)

Step 2:

Place a Minecraft on the track. Don't hop in it! Just walk into it and it should start going around the track on its own.

Step 3:

Once the Minecraft is going around the track spawn any mob (evan endermen) on the track.

Step 4:

The cart should pick up the mob as it moves round the track.

Step 5:

Now you have a mob rollar coaster