Pressing a key that is not included in script and spams particles that should be spawned only once?

I've made a script that basically gives me two different abilities and modes when I press Z. It works at all, but when I press another key that isn't Z it spams the particles that appear in each mode. Can anyone recognize the reason?

local m = game.Players.LocalPlayer:GetMouse()
local character = game.Players.LocalPlayer.Character
local fire = "nou"
local ice = "nou"

db = true
m.KeyDown:connect(function(k)
k = k:lower()
if k == 'z' then
    if script.Mode.Value == "" then
        script.Mode.Value = "Ice"
    elseif script.Mode.Value == "Ice" then
        script.Mode.Value = "Fire"
    elseif script.Mode.Value == "Fire" then
        script.Mode.Value = ""
    end
end


if script.Mode.Value == "Ice" then
    --Attiva una variante
    ice = "activated"

    --Qui modifichi le vesti - Modify old clothes
    script.Fire:Clone().Parent = character.LeftFoot
    script.Fire:Clone().Parent = character.LeftHand
    script.Fire:Clone().Parent = character.LeftUpperLeg
    script.Fire:Clone().Parent = character.LeftUpperArm


    --Rimuovi vecchie particelle - Remove old particles
    if fire == "activated" then
    character.RightFoot.Sparks:Destroy()
    character.RightHand.Sparks:Destroy()
    character.RightUpperLeg.Sparks:Destroy()
    character.RightUpperArm.Sparks:Destroy()
    character.RightFoot.Flame:Destroy()
    character.RightHand.Flame:Destroy()
    character.RightUpperLeg.Flame:Destroy()
    character.RightUpperArm.Flame:Destroy()
    end
    -- Con questo attivi le mosse - Here you activate the abilities
    print("Ice")
    script.Parent.IceX.Disabled = false
    script.Parent.FireX.Disabled = true

    elseif script.Mode.Value == "Fire" then
    -- Attiva una variante / N/A
    fire = "activated"
    --Qui modifichi le vesti - Here you modify clothes
    script.Flame:Clone().Parent = character.RightFoot
    script.Flame:Clone().Parent = character.RightHand
    script.Flame:Clone().Parent = character.RightUpperLeg
    script.Flame:Clone().Parent = character.RightUpperArm
    script.Sparks:Clone().Parent = character.RightFoot
    script.Sparks:Clone().Parent = character.RightHand
    script.Sparks:Clone().Parent = character.RightUpperLeg
    script.Sparks:Clone().Parent = character.RightUpperArm

    --Rimuovi vecchie particelle - Remove old particles
    if ice == "activated" then
    character.LeftFoot.Fire:Destroy()
    character.LeftHand.Fire:Destroy()
    character.LeftUpperLeg.Fire:Destroy()
    character.LeftUpperArm.Fire:Destroy()
    end

    -- Con questo attivi le mosse - Active the abilities
    print("Fire")
    script.Parent.IceX.Disabled = true
    script.Parent.FireX.Disabled = false

    elseif script.Mode.Value == "" then 

    -- Qui modifichi le vesti / Here you modify the clothes
    if fire == "activated" then
    character.RightFoot.Sparks:Destroy()
    character.RightHand.Sparks:Destroy()
    character.RightUpperLeg.Sparks:Destroy()
    character.RightUpperArm.Sparks:Destroy()
    character.RightFoot.Flame:Destroy()
    character.RightHand.Flame:Destroy()
    character.RightUpperLeg.Flame:Destroy()
    character.RightUpperArm.Flame:Destroy()

    print("Test")

    -- Qui togli le mosse - You deactivate the abilities
    script.Parent.IceX.Disabled = true
    script.Parent.FireX.Disabled = true
end
end
end)