Final answer:
Balder was killed when Hod threw a sprig of mistletoe at him, as Loki convinced Hod to do so during a game.
Step-by-step explanation:
Balder was killed when Loki convinced Hod to throw mistletoe at him during a game. Mistletoe was considered a weak plant by the gods and did not harm Balder except for one sprig which Hod threw. The sprig pierced Balder's chest and killed him instantly.
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