  Interest in the quasar HE0450-2958 arose following the publication of the
non-detection of its expected massive host, leading to various interpretations.
This article investigates the gaseous and stellar contents of the system
through additional VLT/FORS slit spectra and integral field spectroscopy from
VLT/VIMOS. We apply our MCS deconvolution algorithm on slit spectra for the
separation of the QSO and diffuse components, and develop a new method to
remove the point sources in Integral Field Spectra, allowing extraction of
velocity maps, narrow-line images, spatially resolved spectra or ionization
diagrams of the surroundings of HE0450-2958. The whole system is embedded in
gas, mostly ionized by the QSO radiation field and shocks associated with radio
jets. The observed gas and star dynamics are unrelated, revealing a strongly
perturbed system. Despite longer spectroscopic observations, the host galaxy
remains undetected.
