Wacky hidden items have appeared across many Disgaea games and in Disgaea 6: Defiance of Destiny, we have Cerberus suit. This item isn’t particularly useful, it mostly exists to increase movement but it is helpful if you want to move more of jump higher.
This one is rather straightforward. First go to where the data station is and jump on the boxes.
Walk off the map and turn the camera to face your character.
Follow the right path until you find a treasure chest.
Open it and claim your prize. If you’d like multiples, you do unfortunately have to obtain them from item world.