Dry Bones are undead, skeletal forms of the turtle-like race known as Koopas from the Mario series.
Dry Bones are bipedal like their living Koopa counterparts, despite their more reptilian structure. Their skulls feature shadowed eye sockets with what appear to be yellow pupils in them. On their back in the ribcage area is a pale yellow turtle shell.
Usually in the series, Dry Bones are portayed as enemies (at times, even more agressive than normal Koopa Troopas). In some games, they also show unique abilites, such as regenerating when struck down. However, due to the expansive and rather eccentric Mario Series, along with its spinoffs, especially in Sports, Racing and Party game titles, Dry Bones have been known to change their attitude towards Mario and his friends from hostile to simple competitiveness, or sometimes even co-operative, in some cases of team-based play. Occasionally in such titles, they are playable characters.