The trick to the "Package Returned" achievement is forcing a collision state right as the delivery event occurs.

Your search term brings together several key concepts: "Lovely Craft," "piston trap," and the Chinese term "包裹退回" (parcel return) associated with an "achievement." This combination is likely pulling from two different games:

Save up points to buy the automated speed tiers to ensure infinite looping.

He had built a elaborate Piston Trap: a 3x3 grid of sticky pistons hidden under pressure plates. In the center was a slime block, aimed perfectly at a wooden hopper labeled Return to Sender .