Using immuno-electron microscopic methods (FIBSEM-TEM) we have previously reported PACAPergic calyceal axon terminals in the ventro-lateral capsular subdivision of the central amygdala (FENS abstract 2020, 2022) in rat. To further investigate the origin and molecular constituents of these peculiar calyceal terminals, we used fluorogold retrograde and AAV5-EF1a-DIO-hChR2(H134R)-eYFP anterograde tracing in Adcyap1-2A-cre mice and investigated its molecular signature for both presynaptic and postsynaptic components. We report here that this Calyx of Held-like giant synapse terminal has mixed glutamatergic and cholinergic synaptic specifications (Gray type I and II), seen for the first time, at the ultrastructural level, in a telencephalic structure. CeC PKCd neurons, co-expressing VGAT, PAC1, and VPAC2, have been identified as the main post-synaptic target cells. To identify the neuronal population serving as the presynaptic source of this synapse, we studied first the molecular features of the axon terminal, which is characterized by the co-expression of multiple neurotransmitter vesicular transporters, including VGLUT1, VGLUT2 and VAChT, as well as the neuropeptides CRGP and NTs, and calretinin. Fluorogold (FG) retrograde tracing from CEA labeled a cellular subpopulation in the brainstem parabrachial/Kölliker-Fuse (KF) complex expressing the mRNAs Slc17a7, Slc17a6, Chat, Adcyap1, Calb2, Calca and NTs. Highly restricted Cre-dependent eYFP anterograde viral vector labeling within this region of the parabrachial complex, in PACAP-cre mice, revealed Calyx-like ring patterns in CeC. Our observations suggest that signaling from brainstem PB/KF complex to amygdala occurs via a unique synaptic connection characterized by high-fidelity transmission, yet diverse regulation, potentially contributing to general behavioral adaptation to aversive stimuli.