diff --git a/ExternalToolProjects/FakeTemporalAA/FakeTemporalAA.csproj b/ExternalToolProjects/FakeTemporalAA/FakeTemporalAA.csproj
new file mode 100644
index 0000000000..f61ddc82c4
--- /dev/null
+++ b/ExternalToolProjects/FakeTemporalAA/FakeTemporalAA.csproj
@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+	<Import Project="$(ProjectDir)../NET48ExternalToolForm.targets" />
+	<Import Project="$(ProjectDir)../ExtToolCommon.props" />
+	<PropertyGroup>
+		<AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+		<NoWarn>$(NoWarn);IDE0065;SA1200</NoWarn>
+	</PropertyGroup>
+	<ItemGroup>
+		<PackageReference Include="System.Drawing.Common" />
+	</ItemGroup>
+</Project>
diff --git a/ExternalToolProjects/FakeTemporalAA/FakeTemporalAAToolForm.cs b/ExternalToolProjects/FakeTemporalAA/FakeTemporalAAToolForm.cs
new file mode 100644
index 0000000000..d6720cc94f
--- /dev/null
+++ b/ExternalToolProjects/FakeTemporalAA/FakeTemporalAAToolForm.cs
@@ -0,0 +1,83 @@
+namespace BizHawk.Experiments.FakeTemporalAA;
+
+using System;
+
+using BizHawk.Bizware.Graphics;
+using BizHawk.Client.Common;
+using BizHawk.Client.EmuHawk;
+using BizHawk.Emulation.Common;
+
+[ExternalTool(TOOL_NAME, Description = "Naively blends each frame with the previous")]
+public sealed class FakeTemporalAAToolForm: ToolFormBase, IExternalToolForm
+{
+	private const string TOOL_NAME = "Fake Temporal Anti-aliasing";
+
+	private BitmapBuffer? _bbPrev = null;
+
+	[RequiredService]
+	public IVideoProvider? _maybeVideoProvider { get; set; }
+
+	public ApiContainer? _maybeAPIContainer { get; set; }
+
+	private ApiContainer APIs
+		=> _maybeAPIContainer!;
+
+	protected override string WindowTitleStatic
+		=> TOOL_NAME;
+
+	public FakeTemporalAAToolForm()
+		=> _ = _maybeVideoProvider; // used via ToolFormBase.MainForm
+
+	private void ClearDrawingSurface()
+		=> APIs.Gui.WithSurface(DisplaySurfaceID.EmuCore, g => g.ClearGraphics(DisplaySurfaceID.EmuCore));
+
+	protected override void Dispose(bool disposing)
+	{
+		ClearDrawingSurface();
+		base.Dispose(disposing);
+	}
+
+	public override void Restart()
+	{
+		_bbPrev = null;
+		ClearDrawingSurface();
+	}
+
+	public override void UpdateValues(ToolFormUpdateType type)
+	{
+		const int OPACITY_MASK = 0xFF << 24;
+		static void Invert(Span<int> buf)
+		{
+			for (var i = 0; i < buf.Length; i++) buf[i] = OPACITY_MASK | ~buf[i]; //TODO vectorise?
+		}
+		static int AverageXRGB(int c1, int c2)
+		{
+			//TODO can this be improved?
+			const int R_MASK = 0xFF0000;
+			const int G_MASK = 0xFF00;
+			const int B_MASK = 0xFF;
+			var r = (((c1 & R_MASK) + (c2 & R_MASK)) / 2) & R_MASK;
+			var g = (((c1 & G_MASK) + (c2 & G_MASK)) / 2) & G_MASK;
+			var b = (((c1 & B_MASK) + (c2 & B_MASK)) / 2) & B_MASK;
+			var c3 = r | g | b;
+			c3 &= ~OPACITY_MASK;
+			return OPACITY_MASK | c3;
+		}
+		if (type is not (ToolFormUpdateType.PreFrame or ToolFormUpdateType.FastPreFrame)) return;
+
+		var bbCurrent = MainForm.MakeScreenshotImage();
+		var spanCurrent = bbCurrent.AsSpan();
+		Invert(spanCurrent);
+		if (_bbPrev is null) // initialisation
+		{
+			_bbPrev = bbCurrent;
+			return;
+		}
+
+		var spanPrev = _bbPrev.AsSpan(); // was inverted before saving
+		for (var i = 0; i < spanCurrent.Length; i++) spanPrev[i] = AverageXRGB(spanPrev[i], spanCurrent[i]);
+		Invert(spanPrev);
+		APIs.Gui.WithSurface(DisplaySurfaceID.EmuCore, g => g.DrawImage(_bbPrev!.ToSysdrawingBitmap(), 0, 0, cache: false));
+		_bbPrev = bbCurrent;
+	}
+}
diff --git a/ExternalToolProjects/FakeTemporalAA/build_debug.sh b/ExternalToolProjects/FakeTemporalAA/build_debug.sh
new file mode 120000
index 0000000000..c2127aded1
--- /dev/null
+++ b/ExternalToolProjects/FakeTemporalAA/build_debug.sh
@@ -0,0 +1 @@
+../.build_debug.sh
\ No newline at end of file
diff --git a/ExternalToolProjects/FakeTemporalAA/build_release.sh b/ExternalToolProjects/FakeTemporalAA/build_release.sh
new file mode 120000
index 0000000000..801b8e5998
--- /dev/null
+++ b/ExternalToolProjects/FakeTemporalAA/build_release.sh
@@ -0,0 +1 @@
+../.build_release.sh
\ No newline at end of file
diff --git a/ExternalToolProjects/FakeTemporalAA/run_with_tool.sh b/ExternalToolProjects/FakeTemporalAA/run_with_tool.sh
new file mode 120000
index 0000000000..b7cf6138ab
--- /dev/null
+++ b/ExternalToolProjects/FakeTemporalAA/run_with_tool.sh
@@ -0,0 +1 @@
+../.run_with_tool.sh
\ No newline at end of file
diff --git a/ExternalToolProjects/NET48ExternalToolForm.targets b/ExternalToolProjects/NET48ExternalToolForm.targets
index f65ba71ec9..822130c2c6 100644
--- a/ExternalToolProjects/NET48ExternalToolForm.targets
+++ b/ExternalToolProjects/NET48ExternalToolForm.targets
@@ -8,6 +8,9 @@
 	<ItemGroup>
 		<Reference Include="System.Windows.Forms" />
 		<PackageReference Include="System.Runtime.CompilerServices.Unsafe" />
+		<Reference Include="BizHawk.Bizware.Graphics"
+			HintPath="$(MSBuildProjectDirectory)/../../output/dll/BizHawk.Bizware.Graphics.dll"
+			Private="true" />
 		<Reference Include="BizHawk.Client.Common"
 			HintPath="$(MSBuildProjectDirectory)/../../output/dll/BizHawk.Client.Common.dll"
 			Private="true" />