Something I think would be in character for Viper and be a nice buff to go along the several suggestions on this sub is to have the enemies start loudly coughing when they enter Viper's smoke and when they cross her wall, so they'd be and informational tool just like Cypher's cage. Maybe add that sound cue to her ult too, and make the coughing last for a short while after leaving the smoke/wall/ult.

What do you all think about this idea?