Which episode did Daenerys Targaryen lose her dragon, Viserion, to a White Walker's spear?
The Night King, the leader of the White Walkers, threw a spear at Viserion, which killed him.
<START_INST>Which episode did Daenerys Targaryen lose her dragon, Viserion, to a White Walker's spear?<END_INST><START_CTX><END_CTX><START_A>The Night King, the leader of the White Walkers, threw a spear at Viserion, which killed him.<END_A>