In my Actifit report yesterday @jfang003 replied asking if aliens would have bones. I was reviewing an Isaac Arthur video and I can't speak for him but my response would be that I would expect most intelligent alien species to have at minimum a hard skull encasing the brain. Maybe not necessarily "bone" but some dense material to help protect the brain.
An alternative @jfang003 proposed is an alien slime mold. I can imagine some kind of alien amoeba-like single-cell that fuses to others of its kind. Individually each cell has no intelligence but by grouping and networking together there could be emergence of a type of intelligence. Its "brain" would be distributed so it wouldn't have as much of a need for a hard protective brain enclosure. That type of life probably couldn't develop tools and become space-faring though.
Is there intelligent slime somewhere in the Universe?
I don't know.
Posted with STEMGeeks