A spark plug includes a housing, a center electrode disposed within the housing, and a ground electrode cooperating with the center electrode to generate a spark. The ground electrode further includes an arm having a main body and a base, a pad fixed to the base, and a covering affixed to at least one of the main body and the base. The main body is fixed to the housing. The covering alters a dielectric constant of the main body or a dielectric constant of the base to create a difference in the dielectric constant of the main body and the dielectric constant of the base and focus the spark on the pad.