Avengers #186 (1963 Series)

The situation in Transia has taken a turn for the worse! While Bova tells Pietro about his childhood, Wanda wages a life-and-death struggle against Modred the Mystic atop Wundagore Mountain! Unfortunately, the battle goes poorly and an elder demon from centuries ago possesses the Scarlet Witch! Recognizing the imminent danger, Quicksilver makes a mad dash to the only telephone in the village...and places a desperate call to Avengers Mansion! Can the lightning-fast avenger contain his sister's destructive rampage while the other avengers travel to Transia? Hope is fading by the minute! Flashback cameos by the High Evolutionary, Magda, Jonathan Drew, Robert Frank, and Madeline Frank.

First appearance Chthon
First appearance Boua