Future Trunks super saiyan 2

 Future Trunks simply kept increasing his power, unaware that his speed was greatly decreasing and his energy consumption greatly augmented to a point where sustaining the state would prove to be a problem. His body became too bulky and slow from the large quantity of muscle and this gave Cell the upper hand, despite not even having powered up and slightly below Trunks in brute strength. Trunks quickly realized that he was too slow and gave up hope right before Cell's eyes