This article addresses one of the aspects of ritual communication among the Matsigenka: that of the use of sound icons, or ideophones, during the enunciation of Marentakantsi songs. In the sung repertoire of the Matsigenka oral tradition, there are two categories of songs, those that are considered the devices of intraspecific interaction called matikagantsi, and those that concern us here, the marentakantsi, which fall under interspecific interaction. Only initiates, during ritual contexts of enunciation, can sing the latter. These ritual sessions take place at night, in the dark, under the influence of psychotropic substances and bring together a ritual specialist and his wife, one or more members of the collective, as well as auxiliary spirits. Singing and the use of sound icons during its performance are constitutively related to intoxication and interaction with spirits. When all the conditions are met, this interaction leads to the transformation of the specialist into an auxiliary spirit. The transformation (ipigatake) occurs in a state of poisoning (ipigatake) and it is for this reason that the marentakantsi, considered as poisoning sings, are simultaneously chants of transformation.