The Plunger's Office
From A KoL Wiki

He can combine your items for free without the use of meat paste.
The Plunger is located in Inside Degrassi Knoll, which can only be accessed after ascending under the Mongoose, Wallaby, or Vole moon sign.
The Plunger takes your items, fuses them together by mashing them with his plunger, and hands you the result.
Those items don't combine to make anything, Citizen. Perhaps we should try something else.