It's possible to get this after completing the Battle Tower back in the Baron Desert and getting the Key from Barracuda Joe. Go to the Tangle Forest and go to a Rock Cave in the first layer of the stage, there, you'll get the Elephant Dance.
After that, go back to the Baron Desert and go to another Rock Cave, there will be a huge rock inside of it, destroy it with the Elephant and it will reveal yet another Rock Cave, enter it and proceed until you unlock the Elephant Stomp, once you leave, there will be a row of 6 Blocks on the floor, transform into the Elephant, stomp them all and you'll unlock the achievement