Additionally, for some reactions, only one reaction can occur at a time. For example, if you apply non-heavy Pyro to a Frozen aura that has an underlying Hydro aura, only melt occurs. If the underlying aura is Cryo (which can be melted), melt will occur and reduce both the Freeze and the original Cryo aura. It is possible for a reaction to affect both auras, while some reactions only affect one aura. For example, a sufficiently strong anemo aura application can cause a double swirl where both the underlying hydro aura and the frozen aura are swirled. This also occurs with heavy attacks, which can cause both shatter and a reaction based on the underlying aura. For example, if an enemy who is both frozen and affected by underlying hydro is hit with a heavy pyro attack while frozen, both shatter and vaporize will occur. If the same enemy was affected by underlying cryo instead, melt would occur. Both scenarios require an underlying aura to be applied to an enemy; without an underlying aura, only shatter will occur. This effect applies to all heavy elemental attacks.