Srimad Bhagavatam Canto 08, Chapter 11, Text 40

SB 8.11.40

na suskena na cardrena
 jahara namuceh sirah
tam tustuvur muni-gana
 malyais cavakiran vibhum
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Thus Indra, King of heaven, severed Namuci’s head with a weapon of foam, which was neither dry nor moist. Then all the sages satisfied Indra, the exalted personality, by showering flowers and garlands upon him, almost covering him.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
In this regard, the sruti-mantras say, apam phenena namuceh sira indro ’darayat: Indra killed Namuci with watery foam, which is neither moist nor dry.
Srimad Bhagavatam Canto 08, Chapter 11, Text 39
Srimad Bhagavatam Canto 08, Chapter 11, Text 41