Maybe make it more useful or replace with a useful spell? Fireball is straight up better in all situations.
It could be made more situational? It could enhance fire damage against all people in the room for a certain amount of time?
Or has a chance of blinding people? Etc...
I agree.
The same goes for the cone of fire.
The difference in damage is marginal for double the mana that it consumes.
If you look it up in D&D DragonLance
Description: 'Incendiary Cloud'
A swirling mass of smoke and blazing embers billows out to fill a 20-foot-radius sphere, centered on a point you choose within range. The cloud spreads around corners, and its area is heavily obscured.
When the cloud appears and at the start of each of your turns, it deals 10d8 fire damage to creatures inside (Dexterity save for half). The cloud moves 10 feet away from you at the start of each of your turns, rolling along the ground. It ignites flammable objects that aren’t being worn or carried.
while Cone of Fire.
Description: 'Cone of fire'
The caster exhales or emits a cone of intense fire in a cone-shaped area.
Every creature in the area must make a Dexterity saving throw.
On a failed save, the creature takes full fire damage; on a successful save, they usually take half damage.
The damage is typically around 6d6 fire damage at 5th level, scaling up with higher levels.
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