Valmiki Ramayana Sundara Kanda Sarga 38 Shloka 30

सः he, Rama, संस्तरात् from his darbha mat, दर्भम् darbha grass, गृह्य took out, ब्राह्मेण अस्त्रेण invoked the weapon of Brahma into it by reciting the mantra, योजयत् discharged, सः that, दीप्तः blazed, कालाग्निरिव like the fire of death, द्विजम् the bird, अभिमुखः towards, जज्वाल glowed.

'Taking out a blade of darbha grass from your mat, you invoked the weapon of Brahma by reciting the mantra. Then you discharged it which blazed like the fire of death and went spearheading towards the crow.