In the anime this power up does not appear, with Future Trunks instead using the similar Super Saiyan Anger form.
This state is identical to the ordinary Super Saiyan 2 form, however when powering up into it the user possesses more sparks in their aura and their hair becomes even more spiked.
Usage and power
In the Dragon Ball Super manga it is revealed that like how the original Super Saiyan form could be upgraded through training to gain power enhancements or become mastered, the Super Saiyan 2 form can be improved as well. By training yourself to death with the Super Saiyan 2 form, you gain the ability to power up into this enhanced state. The strengthened Super Saiyan 2 State is far more powerful than the Super Saiyan 2 state, as it increases the user's power as much as a Super Saiyan 3 (around four times greater than the regular Super Saiyan 2). Eventually, after training with Vegeta, he became stronger in this State, able to hold his own against Goku Black as a Super Saiyan Rosé and Future Zamasu long enough for Goku and Vegeta to travel back to the present.
In the manga, Future Trunks managed to obtain this form through intense training after realizing that Super Saiyan 2 was not his limit. Future Trunks reveals this form to Goku during their sparring match when Goku transforms into a Super Saiyan 3 to impress Future Trunks - to which Future Trunks responds by taking on this state, prompting Vegeta to note with surprise that Future Trunks' strength was a match for Super Saiyan 3 Goku's, and requiring Goku to become a Super Saiyan God to take down Future Trunks. Future Trunks uses this form once again in the future, able to briefly take on Super Saiyan Rosé Goku Black and take down Future Zamasu. However, once Goku and Vegeta travel back to the present, Future Trunks is beaten down easily in this state by Black. Later, Future Trunks uses this state again when confronting Goku Black to save Gowasu - with Black responding by transforming into Super Saiyan Rosé, Future Trunks manages to hold his own just long enough for Goku and Vegeta to return - though at that point Black has Future Trunks at his mercy.