A cassowary and his offspring◊ (the male alone raises the chicks, and will not hesitate to kill or at least horribly maim you if you get anywhere close to the babies)
Similiarly, Zoro's reaction to Chopper getting hurt.
Whitebeard is known to snap when someone threatens or hurts one of his crew members. So when Akainu killed Ace, he went into a terrifying Tranquil Fury, delivering a brutalbeatdown.◊ The chapter title was fittingly called Silent Rage.
