You mean the transfer of inertial energy? It is a variation of kinetic energy. But to visualize that sort of energy transfer is impossible, because it is something we defined. It doesn't have a form as such, and can only be imagined in the form we defined it in, as we do with all transfer of energy (except perhaps electrical), if that makes sense.

Anywho, the way I think about energy transfer is with forces. One particle hits another, the particle will experience a force at the contact surface, with up to three vector directions depending on the axial system and how you define it. That force contributes to a change in velocity, etc.