Neutron star (NS) merger events are preceded by a common envelope phase, possibly with a NS entering the envelope of a massive giant. I discuss the interaction between the NS and the envelope, specifically accretion at a high rate onto the NS followed by jets that collide with the envelope, which can lead to pre-explosion outbursts and supernova impostors. Such a model can account for the very high velocity in the 2011 outburst of SN 2009ip. The ejecta of the terminal supernova following the collapse of the massive giant’s core can collide with the circumstellar matter expelled in the outbursts driven by the NS. In extreme cases the NS will spiral in all the way to the core of the massive giant and disrupt it completely in an energetic event termed a 'common envelope jets supernova', as suggested by Soker & Gilkis for the peculiar supernova iPTF14hls. I will discuss the evolutionary channels leading to jets launched from a NS companion entering the envelope of a massive giant, which can manifest as pre-explosion outbursts, energetic terminal explosions, or supernova impostors.