Kill player if they have certain value?

Hello, one way to do this would be to connect .Touched to the part, .Touched gives a parameter for the part that touched the box, we can check if the part is a rig by checking if a humanoid exists in the character, if there is a humanoid, we know it's a rig, but to check and get the player, we can use GetPlayerFromCharacter to get it, then we just get the stage value and check if it's greater than 1, if it is, set the humanoid health to 0

local players = game:GetService("Players") -- This will be useful, and it is good practice to use GetService
local part = script.Parent -- Assuming this script is inside your invisible box
local valueThatKillsYouLol = 1 -- you can just change the name if you want, this is optional if you want more than 1 invisible box, we are gonna check if the stage value is greater than this (e.g 1)

part.Touched:Connect(function(hit)
    local humanoid = hit.Parent:FindFirstChild("Humanoid") -- We use FindFirstChild because it returns nil if the child is not found, because we don't know if the part that touched is a character
    if (humanoid) then
        -- If it's a character
        local player = players:GetPlayerFromCharacter(script.Parent) -- Getting the player
        if (not player) then
            -- If the character is a dummy or an npc
            return -- don't go further than this line, this return will stop the code
        end
        local leaderstats = player:FindFirstChild("leaderstats")
        if (leaderstats) then -- if the player's leaderstats are there and loaded
            local stage = leaderstats:FindFirstChild("Stage")
            if (stage) then
                if (stage.Value >= valueThatKillsYouLol) then
                    -- If it's greater than the value to kill you
                    humanoid.Health = 0 -- Kill the player
                end
            end
        end
    end
end)