Midsummer Ground Flower

Midsummer Ground Flower is a firework item that darts around on the floor and crackles and throws out yellow sparks and shoots up into the air and EXPLODES! Wheeeee!

Source
During the Midsummer Fire Festival this item can be purchased for from:
 * in Stranglethorn Vale
 * in Dun Morogh
 * in Elwynn Forest
 * in Durotar
 * in The Barrens

During the Harvest Festival this item can be purchased for from:
 * outside the entrance of Ironforge
 * outside the entrance of Orgrimmar