Fallacies, Part 2

When I read Critical Thinking for the class I read along pages 199-200.  These few pages contain information pertaining to many fallacies and the structure of fallacies.  These pages struck me as most interesting based off of the many examples that we are given for each structural type.  I found myself asking many question about each fallacy in particular, and the idea as a whole.  Page 199 in Epstein's text first explains what fallacies are in a whole, and how some can be bad because of their structure.  Page 200 contains 13 examples of fallacy types and similar types of valid or strong arguments.  For example, a fallacy type called "arguing backwards will all" All S are P. a is P. Therefore, a is S.  This example created some questions for me, which I tried to answer.  What if I just put random nouns in these variables places?  All elephants are big. Mike is big.  Therefore Mike is an elephant.  Does this argument hold?  Is is valid?  I couldn't answer these questions because I began to throw in different nouns and kept coming up with different examples.  It all became kind of confusing to be honest.  If anyone could help clarify please let me know in a comment.