Dragon's Rage

Channeling the might of dragons, you augment your physical might. While this spell is active, you gain the following benefits:

• You add twice your strength modifier to damage rolls of melee attacks
• You may wield one two-handed and/or heavy weapon in one hand with no disadvantage to your attack rolls. You cannot dual wield two of these weapons, however.
• You gain temporary hit points equal to your Strength modifier + your warlock level.
• You gain resistance to nonmagical bludgeoning, piercing and slashing damage, as well as one damage type of your choice from acid, fire, cold or lightning. If you are already resistant to these damage types, you gain immunity, even if the damage is magical.

However, this spell is very physically taxing.

• You cannot concentrate on spells while this spell is active (with the exception of claws of the dragon and dragon's breath.)
• If you end this spell early, you gain one level of exhaustion.
• You have disadvantage on all Wisdom and Intelligence saving throws.
• Choose from acid, cold, fire or lightning. You gain vulnerability to this damage type. This cannot be the same damage type as you chose for your resistance.
• You must wait one round before casting this spell again.