Viper was a later addition to the #9206 glow in the dark ghost mask with shroud line up in 1997. Its fanged teeth and evil expression differentiates it from other styles. This mask was launched on the new Fearsome Faces 'bat & moon' aesthetic branded cards and served as the poster child for the ghosts- being the only image shown on the ghost tags. Masks from this era excite many who remember the scented additive that gave them a particular vanilla aroma.
It was not phased out until recent, and was last seen in 2017 in a non-glow white soft pvc material.
*Some fans often mislabel this mask as "Fang", but we recently learned from Brigitte Sleiertin-Linden that she called this mask Viper when designing it. This was confirmed by Frank McGovern, who referred to his cobra-like mask as the 'Fang' ghost.