Ravenlok

After defeating Ugsak the Glutton you will be given a "Slimy Key" take this key back the way you came to the main teacup area, then go up the hill immediately above you, run through this area around a corner to the Slimy Chest, you can now use the key on the chest and the achievement is yours. You may have to accept the slimy chest quest first. Inside the chest is the Blue Cheese Cupcake that you give to the little mouse next to the mirror in the Victorian House.


Some users report needing to accept the slimy chest quest BEFORE getting the key, I was able to just take the key straight to the chest and accept then complete the quest in one go but sounds like it can vary. I have noticed achievements can be a little buggy or lagged.

In the Tea Party area, there's a locked chest on the left path from where Toppy is standing (this path also has the remaining tea cups for the quest), interact with it to start the Chest quest then go on to the right path for a boss fight to get this key and unlock the slimy chest for achievement and quest completion.


Timestamps:
00:00:00 - New Home
00:00:15 - "Once Upon a Time" Achievement
00:00:25 - "Waff!" Achievement
00:05:15 - "Into the Barn" Achievement
00:07:15 - "A Prophecy" achievement
00:07:30 - 01/18 Figurine
00:07:40 - "Vibing" Achievement
00:14:55 - "Sword, Shield, Fight!" Achievement
00:17:10 - Mushroom Forest
00:19:40 - "A Grand Visit" Achievement
00:20:05 - 02/18 Figurine
00:23:25 - 03/18 Figurine
00:26:50 - "Fun Guy" Achievement
00:27:35 - 04/18 Figurine
00:38:35 - 05/18 Figurine
00:38:45 - "Well Rested" Achievement
00:44:40 - "Tragic Brave" Achievement
00:51:45 - "Awakened Spirits" Achievement
00:52:15 - Mask Mansion
00:55:10 - 06/18 Figurine
00:59:25 - "Glimmer of Hope" Achievement
01:00:00 - "An Actor!" Achievement
01:02:55 - "Surprise!" Achievement
01:05:45 - 07/18 Figurine
01:10:25 - "Curtain Call" Achievement
01:12:10 - Tea Party
01:14:15 - 08/18 Figurine
01:14:30 - "Teacups for Toppy" Achievement
01:16:30 - "Piece of Cake" Achievement
01:17:15 - "Gooey Delight!" Achievement
01:18:20 - 09/18 Figurine
01:24:50 - "Nightmare Fuel" Achievement
01:25:20 - "It's Pointy!" Achievement
01:26:10 - "Take Heart" Achievement
01:26:20 - Way To Labyrinth
01:26:50 - "Little Shop" Achievement
01:29:35 - 10/18 Figurine
01:31:25 - 11/18 Figurine
01:32:20 - "The Guardian" Achievement
01:33:10 - "Frog Facts!" Achievement
01:39:35 - "All That Glistens" Achievement
01:41:30 - "Ancient Wisdom" Achievement
01:45:20 - 12/18 Figurine
01:54:00 - "Spellbound" Achievement
01:55:50 - Clock Tower
01:58:05 - "Extinct Again!" Achievement
02:01:00 - "Bird of Prey" Achievement
02:01:35 - 13/18 Figurine
02:01:55 - 14/18 Figurine
02:02:45 - "Stardust" Achievement
02:03:25 - "Extraordinary!" Achievement
02:04:15 - "Heartbreaker" Achievement
02:05:35 - "Kidnapped!" Achievement
02:06:05 - Labyrinth Of Mirrors
02:08:15 - 15/18 Figurine
02:09:50 - 16/18 Figurine
02:13:15 - "Trick Question!" Achievement
02:13:35 - Greenhouse
02:15:10 - "Stronger!" Achievement
02:16:40 - "Shopping Spree!" Achievement
02:25:05 - "Pull the Plug" Achievement
02:25:30 - 17/18 Figurine
02:26:00 - "Flower Power" Achievement
02:26:45 - "All Heart" Achievement
02:29:05 - "Bombs Away!" Achievement
02:29:50 - Queen's Castle
02:33:40 - "Soul Slayer" Achievement
02:33:50 - 18/18 Figurine
02:33:55 - "Dance Master" Achievement
02:35:20 - "Mirror, Mirror" Achievement
02:43:00 - "Max Level!" Achievement
02:44:45 - "Final Showdown" Achievement
02:50:00 - "The Downfall" Achievement
02:50:30 - "Spot of Tea?" Achievement
02:50:50 - "Crowned" Achievement
02:52:55 - "Going Home" Achievement
02:53:40 - Subscribe!