When Mist of Panderia came out Blizzard introduced scenarios. These scenarios were meant to be short wait time and quick to run. Think of  it as a mini dungeon. These scenarios have been since conception a face roll and for many players boring and because of  this they (Blizzard) introduced Heroic Scenarios. These new Scenarios are not random, you have to form a 3 man group and they can be done without heals but it is not recommended. They have been tough and fun. Below is a screenshot from a scenario I did tonight and an achievement I got from it.