The Blast-o-Matic (ブラストマティック, Blast-o-Matic) is King K. Rool's Final Smash in Super Smash Bros. Ultimate. It also appears as a collectible support spirit that increases the damage dealt to giant opponents.
When this Final Smash is used, King K. Rool will stomp, stunning any nearby opponents, and lunge forward while catching those in his path. If at least one opponent was caught, a cutscene plays in which K. Rool is sitting on his throne laughing in Crocodile Isle and presses a button twice. The Blast-o-Matic cannon on the isle then fires on Donkey Kong Island. All captured opponents are shown to be trapped in the eyes of the stone sculpture of Donkey Kong as the Blast-o-Matic's laser blasts through it, destroying the island and dealing massive damage to them.
In Donkey Kong 64, due to his numerous defeats against Donkey Kong, King K. Rool sought revenge by destroying Donkey Kong Island (Kong Isle in Donkey Kong 64). He had Snide, his chief technician, develop the Blast-o-Matic, a high power laser cannon capable of destroying Kong Isle. K. Rool later incorporated the Blast-o-Matic into Crocodile Isle and set course to Kong Isle; however, a disagreement between the two Kritters in charge of Crocodile Isle's steering wheel caused the naval fortress to crash into a rock, damaging the Blast-o-Matic. When Crocodile Isle arrived at Kong Isle, K. Rool ordered his minions to capture Donkey Kong's friends and to steal his Banana Hoard in order to give his Kremlings time to fix the Blast-o-Matic before Donkey Kong can stop him. During the Game Over sequence of Donkey Kong 64, or when the Kongs fail to disarm the fully repaired Blast-o-Matic in Hideout Helm, K. Rool readies the laser cannon to fire on Kong Isle; however, the destruction of the isle wasn't actually shown and was only implied.
This Final Smash is based on the implied destruction of Kong Isle during the Game Over sequence of Donkey Kong 64 with minor differences, such as Crocodile Isle being set on a natural island rather than being a naval fortress, Donkey Kong Island more closely resembling its appearance from Donkey Kong Country, and K. Rool hitting the chair with his opposite arm.