Sparky appears in Balloon Fight as the alarm icon. He has a watering can and stands on a cloud.
Sparky appears to just be a normal human, wearing a hat, shirt, and striped shorts. He stands on a cloud, with one hand behind his back, and the other holding a watering can in front of him.
When the alarm goes off, Sparky will begin to spill water out of his watering can. If the player isn't currently in a game, the system will make a beeping sound, but if you are currently playing the game, no sound will play. Sparky only appears in the corner if the alarm is set.
His name is likely a reference to the sparks which float in the sky as obstacles in the game.
While the fact that he stands on a cloud and has a watering can is a reference to rain, rain wouldn't appear in the Balloon Fight series until Balloon Kid, and then wouldn't appear again until Balloon Trip Breeze in Nintendo Land.