You asked what is a virus like particle. A virus high-jacks cell machinery to reproduce itself and may bud of to make new infective virus particles, sometimes they can be seen as membrane blebbing.
They look like virus and sometimes can be seen blebbing on the cell surface but you may need to find the viralRNA/DNA and show infection to confirm it is a live virus
Many years ago I made a B cell line. We fused a B cell with a B cell plasmocytoma (A plasma cell tumour) to do some antigen binding assays. We called it BCTL-1 (Big Chief Team Leader 1 at the suggestion of someone in the lab…someone elses was once called FUJA..won’t say why). I was quite excited about it and please with myself by then I did some electron microscopy of the line. We saw virus like particles budding from the cell. Were they virus? I was not going to find out. Were they a health risk producing something that could infect a human? We then froze them down and they are sat in secure freezer storage at about -200 degrees centigrade.
However I then checked many of the standard cell (tumour) lines from rodents, such as those used to make monoclonal antibodies (NS1), T cell hybridomas, macrophage lines etc, etc. These all contained virus-like particles. Maybe the virus was the cause of the cell becoming a tumour or may be a consequence of rapid division. Mice like humans harbour many endogenous retro virus is one of them important in MS