-- LocalScript in StarterGui

local player = game.Players.LocalPlayer
local character = player.Character or player.CharacterAdded:Wait()
local hrp = character:WaitForChild("HumanoidRootPart")

-- Create GUI
local screenGui = Instance.new("ScreenGui", player.PlayerGui)
local button = Instance.new("TextButton", screenGui)
button.Size = UDim2.new(0, 200, 0, 50)
button.Position = UDim2.new(0.5, -100, 0.8, 0)
button.Text = "Self Fling!"

button.MouseButton1Click:Connect(function()
    local bv = Instance.new("BodyVelocity")
    bv.Velocity = Vector3.new(math.random(-200,200), 500, math.random(-200,200))
    bv.MaxForce = Vector3.new(1e5,1e5,1e5)
    bv.Parent = hrp
    game:GetService("Debris"):AddItem(bv, 0.5) -- remove after 0.5s
end)