Sad Dragon was released in the Beta 7.6 update, alongside 13 other cards. Previous Versions can be found here.

Sad Dragon is the 2nd card to gain the Dodge ability (the first being Sans). But while it can only dodge once unlike Sans, it can be useful to prevent Justice's passive from damaging it, making Sad Dragon work like a damage sponge.

It can also be useful by applying Taunt to it with Protection (in Patience) or Glad Dummy (in general).