Tsar Bomba

Overview
The Tsar Bomba [Царь Бомба] is the Evolved Reborn variant of the Big Bertha, believed but not confirmed to be released in the New Heights Update. With Foxy recently teasing new evolutions on his Twitter along with this one, it's very likely to be coming in the next update.

Trivia

 * This item's name is a reference to the 1961 Soviet nuclear weapon, which was the largest nuclear weapon ever detonated in the history of humanity with the explosion power of 50 megatons of TNT.