World 7 - Level 8
Move the steel box one step left along the yellow arrow. Then, using both Stinky and Loof to retrieve the second box below, trap and explode the Kaboom! at the yellow "X". Retrieve seven steel boxes from the stacks by positioning Loof at the green "X" and having Stinky push boxes in front of Loof. The first six can be dumped into the Lava along the green arrow - make sure you do not step onto the conveyor belt yourself though! Get the seventh box out of the room and into position at the black "X", but don't push it onto the conveyor belt yet. Move Stinky to the light blue "X" first, then have Loof push to box in. Now push the box south and move Stinky to the white "X". Have Loof deposited the box in front of Stinky, and then get to a safe spot on the bridge. Use the box to trap and explode the Kaboom! at the purple "X" (you'll need to Rainbow coins for that - don't collect them first!), and exit the level.