#18080, by using the new UA Wild Soul barbarian subclass

You have to be at least a level 3 barbarian with the new Path of the Wild Soul subclass (from Unearthed Arcana: Barbarian and Monk). You must be surrounded in a speaker by 1808 enemies, then enter a Rage; roll a 1 on the d8 from the Wild Surge table, causing this result:

Necrotic energy bursts from you. Each creature within 30 feet of you takes 1d10 necrotic damage, and you gain temporary hit points equal to the sum of the necrotic damage dealt to the creatures.

And then you must roll a 10 on the d10 for damage. Thus, you get temp HP equal to 10 times 1808, for a total of 18080 temp HP.

18080, by using the new UA Wild Soul barbarian subclass

You have to be at least a level 3 barbarian with the new Path of the Wild Soul subclass (from Unearthed Arcana: Barbarian and Monk). You must be surrounded in a speaker by 1808 enemies, then enter a Rage; roll a 1 on the d8 from the Wild Surge table, causing this result:

Necrotic energy bursts from you. Each creature within 30 feet of you takes 1d10 necrotic damage, and you gain temporary hit points equal to the sum of the necrotic damage dealt to the creatures.

And then you must roll a 10 on the d10 for damage. Thus, you get temp HP equal to 10 times 1808, for a total of 18080 temp HP.

18080, by using the new wotc sub class wild soul You have to be at least a lvl 3 barb with the new sub class and be surrounded in a speaker by 1808 enemies and rage roll a 1 d8 and then a 10 on a d10

#18080, by using the new UA Wild Soul barbarian subclass

You have to be at least a level 3 barbarian with the new Path of the Wild Soul subclass (from Unearthed Arcana: Barbarian and Monk). You must be surrounded in a speaker by 1808 enemies, then enter a Rage; roll a 1 on the d8 from the Wild Surge table, causing this result:

Necrotic energy bursts from you. Each creature within 30 feet of you takes 1d10 necrotic damage, and you gain temporary hit points equal to the sum of the necrotic damage dealt to the creatures.

And then you must roll a 10 on the d10 for damage. Thus, you get temp HP equal to 10 times 1808, for a total of 18080 temp HP.