Yogg into Spontaneous Combustion Fizzled

Hi there! Sorry that I don’t have a clip or screenshot of this. My opponent used Yogg to take my only minion, and one of the random spells cast was Spontaneous Combustion. However, it didn’t do any damage to me, and instead just fizzled out.

The wording on the card is “Deal 4 damage to a random enemy. If you played an Elemental last turn, choose the target.” Even though my opponent didn’t play an elemental last turn I think it still should have targeted my face since it was the only valid target.

Are you sure you were a valid target? (i.e. were you Immune?)