When Gnar reaches 100 Fury, he gains access to an alternate set of abilities. After either 5 seconds have elapsed or he casts an ability, Gnar will transform into Mega Gnar for 15 seconds while his Fury depletes. Once his Fury is exhausted, Gnar will return to normal and cannot gain Fury again for 15 seconds. Gnar's two ability sets share the same cooldowns.
Gnar gains different bonuses based on his current form.