what is this movie called?

I saw it on ITALIAN TV from what I remember a MANY (25/30) years back. It's
AMERICAN
. I don't remember the whole story but remember
a scene in a hospital where a male patient was attackeb and killed
maybe eated too  by something coming from under his bed.
I don't remember exactly how was the beast, but I think it looks like
a big turtle.
I were  very young and scared.
It was in b/w.
grazie.