diff --git a/src/main.rs b/src/main.rs
index 99e92e7..fd3e124 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -86,5 +86,5 @@ fn spawn_machine_ui<M: SpawnUi>(
 ) {
   let _entity = event.target;
   // TODO: Hook up the Fuel component (and spawn one so that I can)
-  M::spawn_ui(commands, theme);
+  M::spawn_ui(commands, theme, event.target());
 }
diff --git a/src/widgets/machines.rs b/src/widgets/machines.rs
index d684239..f3ff949 100644
--- a/src/widgets/machines.rs
+++ b/src/widgets/machines.rs
@@ -7,7 +7,7 @@ use crate::{
 };
 
 impl SpawnUi for CuttingMachine {
-  fn spawn_ui(mut commands: Commands, theme: Res<UiTheme>) {
+  fn spawn_ui(mut commands: Commands, theme: Res<UiTheme>, machine_id: Entity) {
     let base_entity = machine_ui_base(&mut commands, "Cutting Machine", &theme);
     commands.entity(base_entity).with_children(|commands| {
       // Left panel. For fuel or machine stats or whatever.
@@ -58,7 +58,7 @@ impl SpawnUi for CuttingMachine {
 }
 
 impl SpawnUi for RotatingMachine {
-  fn spawn_ui(mut commands: Commands, theme: Res<UiTheme>) {
+  fn spawn_ui(mut commands: Commands, theme: Res<UiTheme>, machine_id: Entity) {
     let base_entity = machine_ui_base(&mut commands, "Rotating Machine", &theme);
     commands.entity(base_entity).with_children(|commands| {
       commands.spawn(FuelGauge::bundle(Entity::PLACEHOLDER));
@@ -93,7 +93,7 @@ impl SpawnUi for RotatingMachine {
 }
 
 impl SpawnUi for FlippingMachine {
-  fn spawn_ui(mut commands: Commands, theme: Res<UiTheme>) {
+  fn spawn_ui(mut commands: Commands, theme: Res<UiTheme>, machine_id: Entity) {
     let base_entity = machine_ui_base(&mut commands, "Flipping Machine", &theme);
     commands.entity(base_entity).with_children(|commands| {
       commands.spawn(FuelGauge::bundle(Entity::PLACEHOLDER));
@@ -128,7 +128,7 @@ impl SpawnUi for FlippingMachine {
 }
 
 impl SpawnUi for TransposingMachine {
-  fn spawn_ui(mut commands: Commands, theme: Res<UiTheme>) {
+  fn spawn_ui(mut commands: Commands, theme: Res<UiTheme>, machine_id: Entity) {
     let base_entity = machine_ui_base(&mut commands, "Transposing Machine", &theme);
     commands.entity(base_entity).with_children(|commands| {
       commands.spawn(FuelGauge::bundle(Entity::PLACEHOLDER));
diff --git a/src/widgets/mod.rs b/src/widgets/mod.rs
index a6ff45f..bbe8d57 100644
--- a/src/widgets/mod.rs
+++ b/src/widgets/mod.rs
@@ -30,12 +30,12 @@ impl Plugin for GameUiPlugin {
   }
 }
 
-/// Anything that can spawn a themed UI should impl this trait.
+/// Machines spawn their UI through this trait.
 ///
-/// This exists mainly so that I can write generic functions and have the *compiler*
+/// This exists mainly so that I can write generic functions and have the compiler
 /// expand the code for me, instead of doing it by hand.
 pub trait SpawnUi {
-  fn spawn_ui(commands: Commands, theme: Res<UiTheme>);
+  fn spawn_ui(commands: Commands, theme: Res<UiTheme>, machine_id: Entity);
 }
 
 /// The base panel for the machines that manipulate the room cards.