Collimated outflows are widespread phenomena in astrophysics, from
stellar jets to radio quasars. When these outflows encounter the
surrounding medium a number of phenomena can occur, including serious
damage to both jet and medium. This talk presents a case study of
such an interaction in a Seyfert galaxy, where strong emission lines
provide important diagnotsic information to help unravel both the
nature of the interaction and the nature of the jet.