Add sprites for RGBass, NeptuneSummon (Megaladon), RGBAlloy, and add animations to rarities

Content/Rarities/DeveloperItem.cs

@@ -1,11 +1,26 @@
 using Terraria.ModLoader;
 using Terraria;
 using Microsoft.Xna.Framework;
+using System;
 
 namespace ForgottenWawiTech.Content.Rarities
 {
     public class FWTDeveloperItem : ModRarity
     {
-        public override Color RarityColor => new Color(255, 0, 255); // Bright magenta color
+        // Smoothly fades between Bright Magenta and Dark Red.
+        public override Color RarityColor
+        {
+            get
+            {
+                // Speed in cycles per second
+                const float cyclesPerSecond = 0.75f;
+                float theta = Main.GlobalTimeWrappedHourly * cyclesPerSecond * MathHelper.TwoPi;
+                float t = (float)((Math.Sin(theta) + 1f) * 0.5f); // 0..1
+
+                Color darkRed = new Color(139, 0, 0); // Dark Red
+                Color brightMagenta = Color.Magenta;   // Bright Magenta
+                return Color.Lerp(darkRed, brightMagenta, t);
+            }
+        }
     }
 }