Deathspore Fungus (5e Hazard)
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A single deathspore fungus fits in a 5-foot square space, and multiple fungi might be encountered in a cluster. A creature that starts its turn or moves within 5 feet of a deathspore fungus for the first time on its turn must succeed on a DC 14 Constitution saving throw or take 10 (3d6) poison damage and 3 (1d6) necrotic damage and be poisoned for 1 minute. A creature poisoned in this way takes 7 (2d6) poison damage and 2 (1d4) necrotic damage at the start of each of its turns. An affected creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
A humanoid that dies while poisoned in this way rises 24 hours later as a zombie, unless it is restored to life or its body is destroyed. A zombie created in this way is considered charmed by the fungus that created it and will not willingly attack other deathspore fungi.
A deathspore fungus has AC 10, 15 hit points, and immunity to necrotic, poison, and psychic damage.