We are reporting the first experimental observation of nanojets formed by heating PbO-coated Pb clusters, which has been predicted theoretically by Moseler and Landman. During heating, the hot liquid is ejected through the broken orifice into a vacuum and forms a condensed trail in the shape of a tadpole, as shown in the transmission electron micrographs. The temperature-variable Raman spectra indicate that nanojet formation is closely related to the heating temperature and thus essentially to the pressure in the coated clusters. The pressure inside the shell rises from the inner core's melting and its confined volume expansion. It then drops after the final explosion, dominating the whole nanojetting process.