Vegeta's ultimate form the power/technique of the Gods of Destruction.

Ultra Ego is one of the most powerful divine techniques in all of DB being the opposite of Ultra Instinct. This battle technique is acquired by training and gaining the power of destruction and it being driven by instincts allow the user to get stronger. Ultra Ego is moving the body freely and a power that is derived solely on instincts is unbounded.
Vegeta's instincts with Ultra Ego is to receive damage and grow stronger. Beerus instincts with Ultra Ego as a God of Destruction is destruction/to destroy allowing him to have no limit to his power. At some point in the DBS story Vegeta will master the technique becoming one of Beerus strongest/greatest rivals along with Goku, before creation comes destruction.
The recent Vjump issue details Vegeta's abilities.
(DBS Manga Vjump Text
(Vegeta's Techniques) Ultra Ego
A divine technique acquired through training with Beerus. It fights instinctively/on instincts, and unleashes attacks charged/imbued with the power of destruction.