Valmiki Ramayana Yuddha Kanda Sarga 80 Shloka 16

समितिञ्जयःwho had acquired the power of being victorious in the wars, सःइन्द्रजित् Indrajith, राक्षसैःfor Rakshasas, by Rakshasas मन्त्रै: uttering ritualistic verses, अग्निम् in fire, हुत्वा offering, नगरात् from the city, अभिनिर्याय departed, अन्तर्धानगतःdisappeared, अब्रवीत् bragged as follows

Indrajith who had acquired the power of being victorious in the wars departed, after uttering ritualistic verses which are known to Rakshasas only and making an offering into fire disappeared and bragged as follows.