Rongorongo

Rongorongo is the sixth and final stage in Spring Sprang Sprung Event.

Near the beginning, a Doge Dark and a Shadow Boxer K will appear. (Order: fight begins, ..., Doge Dark, ..., Shadow Boxer K) When the base takes enough damage, an Easter Duche and an Easter Bunny will appear. A few seconds later, another Easter Bunny appears. We don't know anything's buff.