Thunderclap Fruitcore

To obtain a Thunderclap Fruitcore you'll need to find and destroy the Electro Regisvine on any World Level. The higher your World Level, the higher your chances of receiving multiple materials at once. To receive them you'll need to spend 40 Resin each time you defeat this Boss.

There is no quest requirement to unlock this boss. It is important to note that it is located underground. Refer to the image below for its location:

The core of an Electro Regisvine, wrapped in razor-sharp leaves, wantonly emits Electro energy. The roaring energy rampaging deep within the earth is eager to pour out its rage, thus even tainting these unfortunate vines with its mania, causing them to wail and flail their branches frantically. One can hardly tell whether it longs for others to taste the pain of being continuously electrocuted and charred or if it is struggling, looking forward to its inevitable doom.