diff --git a/src/abilities/Golden-Wyrm.js b/src/abilities/Golden-Wyrm.ts
similarity index 94%
rename from src/abilities/Golden-Wyrm.js
rename to src/abilities/Golden-Wyrm.ts
index 58f3adb14..2eed62603 100755
--- a/src/abilities/Golden-Wyrm.js
+++ b/src/abilities/Golden-Wyrm.ts
@@ -1,14 +1,16 @@
 import { Damage } from '../damage';
-import { Team, isTeam } from '../utility/team';
+import { Team } from '../utility/team';
 import * as matrices from '../utility/matrices';
 import { Creature } from '../creature';
 import { Effect } from '../effect';
+import Game from '../game';
+import { Hex } from '../utility/hex';
 
 /** Creates the abilities
  * @param {Object} G the game object
  * @return {void}
  */
-export default (G) => {
+export default (G: Game) => {
 	G.abilities[33] = [
 		// 	First Ability: Battle Cry
 		{
@@ -48,7 +50,7 @@ export default (G) => {
 			activate: function () {
 				const creature = this.creature;
 				const damage = new Damage(creature, { sonic: 30 }, this._targets.length, [], G);
-				const hits = new Set();
+				const hits: Set<Creature> = new Set();
 				G.Phaser.camera.shake(0.02, 300, true, G.Phaser.camera.SHAKE_HORIZONTAL, true);
 
 				this._targets.forEach((target) => {
@@ -113,6 +115,7 @@ export default (G) => {
 
 				this.game.grid.queryCreature({
 					fnOnConfirm: function () {
+						// eslint-disable-next-line
 						ability.animation(...arguments);
 					},
 					team: this._targetTeam,
@@ -122,7 +125,7 @@ export default (G) => {
 				});
 			},
 
-			activate: function (target) {
+			activate: function (target: Creature) {
 				this.end();
 				G.Phaser.camera.shake(0.02, 200, true, G.Phaser.camera.SHAKE_BOTH, true);
 
@@ -173,7 +176,7 @@ export default (G) => {
 			 * @returns {Hex[]} Refer to Creature.getHexMap()
 			 */
 			_getHexes() {
-				return this.creature.getHexMap(matrices.frontnback3hex);
+				return this.creature.getHexMap(matrices.frontnback3hex, false);
 			},
 		},
 
@@ -218,9 +221,11 @@ export default (G) => {
 
 				this.game.grid.queryHexes({
 					fnOnSelect: function () {
+						// eslint-disable-next-line
 						ability._highlightDestination(...arguments);
 					},
 					fnOnConfirm: function () {
+						// eslint-disable-next-line
 						ability.animation(...arguments);
 					},
 					size: wyrm.size,
@@ -230,7 +235,7 @@ export default (G) => {
 				});
 			},
 
-			activate: function (hex) {
+			activate: function (hex: Hex) {
 				const ability = this;
 				ability.end();
 
@@ -249,7 +254,7 @@ export default (G) => {
 				});
 			},
 
-			_highlightDestination: function (hex) {
+			_highlightDestination: function (hex: Hex) {
 				this.creature.tracePosition({
 					x: hex.x,
 					y: hex.y,
@@ -343,6 +348,7 @@ export default (G) => {
 
 				G.grid.queryCreature({
 					fnOnConfirm: function () {
+						// eslint-disable-next-line
 						ability.animation(...arguments);
 					},
 					optTest: this._confirmTarget,
@@ -353,7 +359,7 @@ export default (G) => {
 				});
 			},
 
-			activate: function (target) {
+			activate: function (target: Creature) {
 				this.end();
 
 				// The health transferred is the creature's missing life, capped to 50.
@@ -416,7 +422,7 @@ export default (G) => {
 			 * @param {Creature} creature Ally creature that could be targeted.
 			 * @returns {boolean} Should the creature be targeted?
 			 */
-			_confirmTarget(creature) {
+			_confirmTarget(creature: Creature) {
 				return creature.health < creature.stats.health;
 			},
 		},
diff --git a/src/ability.ts b/src/ability.ts
index 3c1d6022b..043c7d09d 100644
--- a/src/ability.ts
+++ b/src/ability.ts
@@ -42,7 +42,8 @@ export type Trigger =
 	| 'oncePerDamageChain'
 	| 'onCreatureMove onOtherCreatureMove'
 	| 'onCreatureSummon onDamage onHeal'
-	| 'onStartPhase onEndPhase';
+	| 'onStartPhase onEndPhase'
+	| 'onDamage onStartPhase';
 
 // Could get rid of the union and optionals by creating a separate (or conditional) type for Dark Priest's Cost
 // This might narrow down the types in the constructor by checking `creature.name`
@@ -97,6 +98,8 @@ export class Ability {
 	triggeredThisChain?: boolean;
 	range?: { minimum?: number; regular: number; upgraded: number };
 
+	// Properties that begin with an underscore are used locally in a specific file in the `abilities` directory.
+	// For example: _lastBonus is unique to Gumble.ts.
 	_lastBonus?: number;
 
 	_disableCooldowns: boolean;
@@ -114,6 +117,13 @@ export class Ability {
 	_getMaxDistance: () => number;
 	_directions?: Direction[];
 	_targetTeam: Team;
+	_targets: Hex[];
+	_addOffenseBuff: () => void;
+	_maxTransferAmount: number;
+	_confirmTarget: (c: Creature) => boolean;
+	_damaged: boolean;
+	_executeHealthThreshold: number;
+	_highlightDestination: (...args: any) => void;
 
 	// Below methods exist in Snow-Bunny.ts
 	_detectFrontHexesWithEnemy: () => { direction: number; hex: Hex; enemyPos: Point }[];