Super Saiyan Third Grade

"I know I look like I can, Gohan, but these bulky muscles make it hard to move fast, and if I'm going to beat Cell, I can't have anything slowing me down. I may have great power, but what good is it if I can't catch my enemy? It takes more than brute strength to win a fight."

- — Goku ("The Cell Games") Super Saiyan Third Grade (スーパーサイヤ人第3段階, Sūpā Saiya-jin dai san-dankai; lit. "Super Saiya person Stage 3"), also called Super Saiyan 1.5, is the second branch of advanced Super Saiyan forms, achieved through intense training in the Super Saiyan form. This form is not related to the mastery of the Super Saiyan form (Super Saiyan Full Power). Like the Super Saiyan Second Grade stage, it is a forced increase in the power outputof the initial Super Saiyan transformation. All natural inhibitions of the body are completely removed in this state, resulting in 100% utilization of strength and stamina reserves.

History
After Cell finally reached his Perfect form and observed his body's new features and power increase--as well as easily defeating Vegeta in his Super Saiyan Second Grade form, Future Trunks screamed and became extremely angry at Cell and desperately wanted to destroy him, in which his emotions flooded into his own power, causing him to reach this form out of rage.

Description
To use, the user either must have the default un-mastered Super Saiyan, and can already access or at least have the potential to access the Super Saiyan Second Grade form, or send extremely high amounts of bodily energy into their nerves ten times more than Super Saiyan Second Grade.

In this stage, the Saiyan is similar in appearance to the Legendary Super Saiyan form. The skin of the Saiyan may become slightly redder due to increased blood flow, and muscle size is increased to the point of impracticality. The Saiyan's hair grows bigger, spikier and spreads in different directions. The aura no longer flows upward, but flails outward, with surges of bio-electricity becoming more frequent and prominent. Sometimes, the pupils and irises may temporarily vanish during the transformation. A notable difference between the two forms, however, is that unlike the Legendary Super Saiyan state, the Super Saiyan Third Grade retains the user's height after bulking up, which is especially evident with Future Trunks, where after accessing the form, he is about the same height as Cell like before he transformed, yet with Broly transforming, he was significantly taller than even his standard form, not to mention much taller than the various Saiyan opponents even compared to beforehand.

When using this form, the Saiyan gains a massive amount of strength and power from the energy increased, allowing their power to be almost comparable or equal to Cell's power in his Perfect Form, as well as having high amounts of stamina to easily recover from an attack. However, the user loses a tremendous amount of speed in sacrifice for their power increase. The muscles are so inflated that it is very slow and stressful to move them, and the stress in the form is much higher than Super Saiyan Second Grade. The ability to simply move freely is completely impaired. The energy consumption is initially slow, but it fluctuates as the user grows easily tired and exhausted from trying to move around in the form.

It is an ultimately useless form if the opponent is faster than the Saiyan to begin with, which led to Goku immediately discarding the form upon discovery. It is widely agreeable that the form can't even be mastered due to its massive flaws.