Example sentences:  

Ramayana: Kumbharana was so gargantuan that the monkeys fell back in terror just by seeing him.  

Mahabharata: The Kauravas made a gargantuan arrangement to keep Arjuna away from Jayadratha on the fourteenth day, but Krishna helped Arjuna succeed. 

Bhagavad-gita: The sight of the gargantuan universal form filled Arjuna first with wonder and then with fear.