Uchuu Sentai Kyuranger S01 E10 The Small Giant, Big Star!

"Nine ultimate saviors"

As the other Kyurangers face a crisis when the Orion goes haywire, Lucky takes Kotaro back to Earth, but when they are attacked by the enemy, Big Bear's spirit appears to them, and after witnessing Kotaro's true determination to protect the world, grants him the power to fight as the 11th Kyuranger.