No dragon can resist the Alpha's command. So, he who controls the alpha, controls them all.
~ Drago Bludvist over his Beweilderbeast.
Drago's Bewilderbeast is the secondary antagonist of DreamWorks's 29th full-length animated feature film How To Train Your Dragon 2 and a minor character in How to Train Your Dragon: The Hidden World. He is an evil dragon and Drago Bludvist's assistant. His master raised him from infancy, turning him into a living weapon for him to control other dragons.
His physical appearance matches that of Valka's Bewilderbeast.
During the battle for dominance over the dragon nest between the wild dragons and Drago's forces, Drago brought his "alpha" Bewilderbeast to challenge Valka's "alpha" Bewilderbeast in order to win over the allegiance of nest's dragons. The monster started to attack Valka's Bewilderbeast and gains the upper hand, eventually overpowering Valka's Bewilderbeast and kills him by impaling him with his tusks, subsequently winning the battle and effectively putting all of the nest's dragons under his control. Under Drago's command, the Bewilderbeast puts Toothless under his command to kill Hiccup, but only succeeded in killing Stoick.
Upon returning to Berk, Hiccup and his friends confronted Drago and his Bewilderbeast. After being encased in ice by the Bewilderbeast, Toothless breaks free, enhanced with plasma, and challenged Drago's Bewilderbeast for supremacy. The Night Fury eventually won by breaking the Bewilderbeast's left tusk, defeating him. This caused Drago and his Bewilderbeast to retreat into the ocean, never to return.
How to Train Your Dragon: The Hidden World
The Bewilderbeast can be seen in the Hidden World, free of Drago's control after his defeat, and when Toothless roars as the King of Dragons, the Bewilderbeast accepts him as his new Alpha.
While initially an seemingly evil creature that was happy to work alongside Drago, Drago's Bewilderbeast actually harbors a more sympathetic and tragic nature. Before he had even hatched, his master took him while still in his egg and raised him, battering and abusing him to develop a sense of powerlessness against him and utter obedience to his master. Any perceived weakness was beaten out and he grew up developing the draconic equivalent of Stockholm syndrome and battered person syndrome. For much of his adulthood, the Bewilderbeast followed him and his armada, helping him recruit more dragons for his army.
However, during the battle for Berk, he observed Hiccup and Toothless' relationship to overpower him, and saw Drago being defeated and humiliated. Eventually, he arrived to the Hidden World and assimilated himself into dragon society, happily welcoming Toothless as his king and perhaps even grateful for Toothless for helping him see the error of his ways.
Drago's Bewilderbeast compared to the Green Death.
the Bewilderbeast accepting Toothless as the alpha
How To Train Your Dragon 2 - Battle Of The Bewilderbeast - English-2
This Bewilderbeast and Drago share various similar facial characteristics such as having "dreadlocks", wrinkles, a searching look, broad chin, darker skins than usual Vikings, a well-built physique, and so on.
According to Pierre-Oliver Vincent, Drago's Bewilderbeast is an ultimate counterpart of Valka's Bewilderbeast. This Bewilderbeast is "like those zoo and circus animals that are tortured and forced to "perform".
In the end of How To Train Your Dragon 2, when Toothless defeats the Bewilderbeast, he peacefully bows and retreats underwater. In How to Train Your Dragon: The Hidden World, he bows down to Toothless and accepts in as the alpha, thus is no longer an enemy to Berk.
Besides a war machine, this dragon was also used to pull Drago's ship. First was prior to the execution of Eret and the dragon riders. Drago was beating the chains with his bullhook, possibly asking the beast to increase speed. Second is when Drago summoned the Bewilderbeast, the chains are seen sliding off the shackles on his tusks.
According to the How to Train Your Dragon 2 commentary, Drago's Bewilderbeast is dubbed the "Bewilderbad".
Interestingly when the Bewilderbeast stops controlling Toothless, there's a brief pause of possible concern in the dragon's face as Hiccup is grieving for Stoick. Thus, it is possible that Drago's Bewilderbeast is not always committed to the deeds Drago wants him to do.