This card is needed to Special Summon "Blue-Eyes Shining Dragon". However, when "Blue-Eyes Shining Dragon" was first released in the TCG (in August 2004), this card did not exist then. It would take until January of 2006 for this card to be made available, thus making "Blue-Eyes Shining Dragon" Summonable.
This monster could have been based off of the Godzilla monster King Ghidorah, as they share many similarities being that they are both three-headed dragons, that they are said to be near indestructible, and their primary attacks are bolts of lightning fired from their mouths.
This card was the first Level 12 monster to appear in the anime.