da chicken said:
Aren’t creatures objects? If so, why did they call them out distinctly?
Probably because they just happen to (generally) be animated objects whereas the other “class” of objects referred to in the PHB (i.e. objects) are (generally) inanimate. That’s why Animate Objects are now creatures in the Monster Manual.
If you look at how the word object is used in the book (i.e. how it is used in context), it is implied as a material object (i.e. made of matter). But, the definition of the word object does include anything that can be thought of, hence, literally, your interpretation can be considered valid.
A spell is a one time magical effect. Personally, I think that most people do not think of spells as objects, but rather as effects and would consider the word object as used in context within the book as meaning a material thing which a spell is not.
However, I will concede your literal point.
