The Eggplant is a carriable item in Spelunky XBLA which can be obtained from placing a gift box on a sacrificial altar, which along with causing the eggplant to appear, causes the current level's music to change also. The full extent of the eggplants purpose, or if it even has a greater purpose other than a reference, is at this time unknown.
Derek Yu, the creator of the game, has referenced other games and movies in Spelunky, which has led some to believe the eggplant is either a reference to the Nintendo game Ice Climber in which the most notable vegetable you save is the eggplant, or the Eggplant Wizard from another Nintendo game Kid Icarus.
Some things that could be considered to indicate the eggplant has a greater purpose are
- It is carriable between levels.
- Andy Hull, the co-creator of the XBLA version has jokingly feigned ignorance of the existence of the eggplant when asked about it on his formspring. Here and here.
Video footage of obtaining the item can be viewed below.