This is how you get the 'Down the Rabbit Hole' achievement in Lego Batman for XBox 360.

Details: Use Mad Hatter's mind control ability to walk 5 enemies to their deaths.

This one actually is really simple to do, but you just need a convenient place to do it. The easiest place I found is in Chapter 1: Area 5 of the Villain story. All the way to the right of the start point is a fenced area with a man you can mind control (they are the ones with ?'s above them). Use this to walk him through the hole in the fence at the bottom of the screen 5 times for this one. He respawns, so it's pretty simple.

Enjoy!