Also a rainbow chat

local TextService = game:GetService("TextService")

function rainbowifyText(text)
    local rainbowColors = {
        Color3.fromRGB(255, 0, 0),
        Color3.fromRGB(255, 127, 0),
        Color3.fromRGB(255, 255, 0),
        Color3.fromRGB(0, 255, 0),
        Color3.fromRGB(0, 0, 255),
        Color3.fromRGB(75, 0, 130),
        Color3.fromRGB(148, 0, 211)
    }

    local rainbowText = ""
    local characters = string.split(text, "")

    for i, char in ipairs(characters) do
        local rainbowColor = rainbowColors[(i % #rainbowColors) + 1]
        rainbowText = rainbowText .. "<font color=\"rgb(" .. rainbowColor.R .. ", " .. rainbowColor.G .. ", " .. rainbowColor.B .. ")\">" .. char .. "</font>"
    end

    return rainbowText
end

game.Players.PlayerAdded:Connect(function(player)
    player.Chatted:Connect(function(message)
        local rainbowMessage = rainbowifyText(message)
        game:GetService("ReplicatedStorage").DefaultChatSystemChatEvents.SayMessageRequest:FireServer(rainbowMessage, "All")
    end)
end)