you really gotta calm down, marisa...

Assets/Scripts/Abilities/AbilityManager.cs

@@ -0,0 +1,76 @@
+using System;
+using System.Collections.Generic;
+using UnityEngine;
+using UnityEngine.UI;
+
+public class AbilityManager : MonoBehaviour
+{
+    #region Statication
+
+    public static AbilityManager instance;
+
+    private void Awake()
+    {
+        if (instance != null && instance != this)
+        {
+            Destroy(gameObject);
+            return;
+        }
+        instance = this;
+    }
+
+    #endregion
+
+    public class StoredUpgrade
+    {
+        public AbilityUpgrade upgrade;
+        public int count;
+    }
+    public MarisaAbilityHandler player;
+    public AbilityUpgrade upgradeToAdd;
+    public Button upgradeButton;
+
+    [Header("Upgrades")] 
+    public List<StoredUpgrade> upgradesInventory;
+    private void Start()
+    {
+        upgradeButton.onClick.AddListener((() => AddUpgrade(upgradeToAdd, player.mainAttackInstance)));
+    }
+
+    public void AddUpgrade(AbilityUpgrade upgrade, PlayerAbility ability)
+    {
+        if (!ability.attachedUpgrades.Contains(upgrade))
+        {
+            AbilityUpgrade newUpgrade = Instantiate(upgrade, ability.transform);
+            ability.attachedUpgrades.Add(newUpgrade);
+            newUpgrade.thisPlayerAbility = ability;
+            newUpgrade.ApplyUpgrade();
+        }
+        else
+        {
+            ability.attachedUpgrades.TryGetValue(upgrade, out AbilityUpgrade foundUpgrade);
+            if (foundUpgrade)
+            {
+                foundUpgrade.count++;
+                foundUpgrade.ApplyUpgrade();
+            }
+        }
+    }
+
+    public void RemoveUpgrade(AbilityUpgrade upgrade, PlayerAbility ability)
+    {
+        if (ability.attachedUpgrades.TryGetValue(upgrade, out AbilityUpgrade foundUpgrade))
+        {
+            if (foundUpgrade.count > 1)
+            {
+                foundUpgrade.ApplyRemoval();
+                foundUpgrade.count--;
+            }
+            else
+            {
+                foundUpgrade.ApplyRemoval();
+                ability.attachedUpgrades.Remove(foundUpgrade);
+            }
+        }
+    }
+}