Cranial Dispersion is a symptom combo exclusive to the Necroa Virus DLC which causes zombie brain matter to be propelled forcefully from open head wounds. Infectivity increases when this combo is in play. Cranial Elephantitis and the transmission Air 3 are required. The achievement Use your head is earned for forming the combo.

Symptom Combos in Plague Inc. and Plague Inc: Evolved.
AssassinBath TimeBlind GeniusBlood in the AirBoomerCarpe JugulumCranial DispersionDiscovery ChannelFly MagnetOn The Naughty ListOopsProfuse BleedingProjectile VomitingPublic DefecationRed Ape RedemptionRed RainRude AwakeningRunnerSpitterSwine FluTankUltimate ChristmasVampire BatWalking ContradictionWalking DeadZombie Panic
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