A basic Fusion (v0.2) component that mimics a water ripple.

Ripple.lua

local Packages = game:GetService("ReplicatedStorage"):WaitForChild("Packages")
local Fusion = require(Packages.Fusion)

local Cleanup = Fusion.Cleanup
local Hydrate = Fusion.Hydrate
local Children = Fusion.Children
local Computed = Fusion.Computed
local Tween = Fusion.Tween
local Value = Fusion.Value
local New = Fusion.New

type RippleProperties = {
	Thickness: number?,
	Lifetime: number?,
	MaxSize: UDim?,
	[any]: any,
}

local function Ripple(props: RippleProperties): Frame
	local rippleThickness = props.Thickness or 4
	local rippleLifetime = props.Lifetime or 4
	local maxSize = props.MaxSize or UDim.new(0, 100)
	
	local rippleAlphaValue = Value(0)
	local rippleAlpha = Tween(rippleAlphaValue, TweenInfo.new(rippleLifetime, Enum.EasingStyle.Exponential, Enum.EasingDirection.Out))
	rippleAlphaValue:set(1)
	
	local newRipple = New "Frame" {
		Name = "Frame",
		BackgroundColor3 = Color3.fromRGB(255, 255, 255),
		BackgroundTransparency = 1,
		AnchorPoint = Vector2.new(.5, .5),
		SizeConstraint = Enum.SizeConstraint.RelativeYY,
		
		Size = Computed(function()
			local a = rippleAlpha:get()
			return UDim2.new(maxSize.Scale*a, maxSize.Offset*a, maxSize.Scale*a, maxSize.Offset*a)
		end),

		[Children] = {
			New "UICorner" {
				CornerRadius = UDim.new(1, 0),
			},

			New "UIStroke" {
				Color = Color3.fromRGB(255, 255, 255),
				
				Transparency = rippleAlpha,
				
				Thickness = Computed(function()
					return (1-(rippleAlpha:get() * .5)) * rippleThickness
				end),
			},
		}
	}
	
	do
		local destroyRippleThread = task.delay(rippleLifetime, function()
			newRipple:Destroy()
		end)

		newRipple.Destroying:Connect(function()
			if destroyRippleThread then
				pcall(task.cancel, destroyRippleThread)
				destroyRippleThread = nil
			end
		end)
	end
	
	local hydrateProps = table.clone(props)
	hydrateProps.MaxSize = nil
	hydrateProps.Lifetime = nil
	hydrateProps.Thickness = nil
	
	return Hydrate(newRipple)(hydrateProps)
end

--[[ Example
while task.wait(1) do
	local rippleScale = math.random(2, 6)/6
	
	Ripple {
		Lifetime = 5,
		MaxSize = UDim.new(.25*rippleScale, 100),
		Position = UDim2.fromScale(math.random(), math.random()),
		Thickness = rippleScale*6,

		Parent = script.Parent
	}
end
]]