Try this code
local combat = createCombatObject()
setCombatParam(combat, COMBAT_PARAM_EFFECT, CONST_ME_HEARTS)
setCombatParam(combat, COMBAT_PARAM_TARGETCASTERORTOPMOST, true)
setCombatParam(combat, COMBAT_PARAM_AGGRESSIVE, false)
function onCastSpell(cid, var)
local magical =...