A ninjutsu with pre-eminent destructive power, caused by wildly spinning chakra inside one's palm and compressing it to a high density — the Rasengan. Using the same essentials, but also rapidly increasing the amount of chakra used, results in the Big Ball Rasengan. It was created by Naruto Uzumaki during his training with Jiraiya. Like the original, Naruto uses a shadow clone to help form it but unlike the original technique, the shadow clone helps him to carry it. Compressed to an even higher density than before, the chakra is released all at once as soon as the technique hits the target, releasing an extraordinary destructive power. Proportional to this power, the amount of chakra it consumes is also extraordinary. With him possessing the near-inexhaustible supply of the Nine-Tails' chakra, it could be said that this technique is for no-one but Naruto.
The anime shows how Naruto created this technique. Naruto while training to break out of genjutsu, accidentally released his chakra and created a huge Rasengan. It was bigger than an average Big Ball Rasengan but smaller than the Sage Art: Big Ball Rasengan.
Minato Namikaze's normal Rasengan is roughly the size of the Big Ball Rasengan.
When Konohamaru used this technique in the OVA, he was able to use it with one hand, despite being taught by Naruto, who himself cannot do so.