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Historical Rules · 18 November 2022

Rule 115.4

Official source text from the 18 November 2022 Rules release

Some spells and abilities that refer to damage require “any target,” “another target,” “two targets,” or similar rather than “target [something].” These targets may be creatures, players, or planeswalkers. Other game objects, such as noncreature artifacts or spells, can’t be chosen.

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