The ability bearer becomes immune to fire type moves. When the ability holder is hit by a fire type move, the power of its own fire type moves increases by 50%. This effect does not stack, but it does remain in effect until the ability holder leaves the battle.
In Generation VIII, Pokémon with Flash Fire will attract fire types if first in the party. In a random encounter, there is a 50% chance of encountering a Fire type whenever it is possible.
Flash Fire's effect is similar to Sap Sipper, Lightning Rod, Motor Drive and Storm Drain, though it is limited compared to these due to the fact that it only powers up one type of move instead of increasing a stat.
Flash Fire's outside of battle effect is similar to Lightning Rod, Harvest, Static and Storm Drain