Guild Wars 2

In PvE, if a player is awarded loot by killing a creature and the loot is of uncommon rarity or higher, a chest will appear that contains the loot that would previously have been on the corpse. If the rarity of the loot on the creature is lower than uncommon, the loot will remain on the creature’s corpse.

Read it 3 times but could not imagine what it means.

sounds to me that you loot a chest instead the dead Body when its rare or higher