local condition = Condition(CONDITION_INVISIBLE)
condition:setParameter(CONDITION_PARAM_TICKS, 2000)

function onCastSpell(creature, var)
    local summons = creature:getSummons()

    if not next(summons) then
        creature:getPosition():sendMagicEffect(CONST_ME_POFF)
        creature:sendTextMessage(MESSAGE_STATUS_SMALL, "You have no summons")
        return true
    end

    for i = 1, #summons do
        local summon = summons[i]

        summon:getPosition():sendMagicEffect(CONST_ME_MAGIC_RED)
        summon:addCondition(condition)
    end

    return true
end