Once you have dealt with the energy swarm and unlocked
you will find yourself in a large "outdoors" room with two short tunnels with collectables. Go to the right side of this area to find a very large, non-hostile creature trying unsuccessfully to scale a structure. The creature is blocking a third tunnel entrance. You must go to the entrance above the creature to find a much smaller version of this species (presumably the large ones spawn). Use your bombs to get the little one to move forward and onto elevators you activate, and use your turbo boost (Y) to get it to activate switches you can not reach. Eventually the little one will scurry off screen. This is your cue to exit the area and return to witness the happy reunion, and the achievement should unlock at this point. Now the blocked tunnel is available for you to leave the area.