Snape's and Black's grudges (was: Living with Sirius)

[anneferrel at yahoo.com]

No: HPFGUIDX 28329

> I had a different take on what Snape is thinking when he goes to 
the 
> Shrieking Shack.  After he takes off the Invisibility Cloak, Snape 
> says:
> 
> "I've just been to your office, Lupin.  You forgot to take your 
> potion tonight, so I took a gobletful along.  And very lucky I 
> did . . . lucky for me, I mean.  Lying on your desk was a certain 
> map.  One glance at it told me all I needed to know.  I saw you 
> running along this passageway and out of sight."

<snip of very good analysis> 

If Snape was able to see Lupin on the map, at least up to the point 
that he entered the Shrieking Shack, it would seem that he would have 
noticed Harry, Ron, Black, and Peter on the map as well (as long as 
he looked at the map before they all entered the shack).  I'm 
wondering if he only saw Lupin on the map because the others were 
already in the shack, and went after him as a combination of duty (to 
give Lupin the potion) and a combination of wanting to 'catch him' 
and prove that Lupin is a danger to have at Hogwarts.  I could 
imagine Snape arriving at the Willow and noticing Harry's 
invisibility cloak.  Seeing that, and not knowing that Black and 
Wormtail were inside, he might think that Harry had gone in after 
soon-to-be-werewolf Lupin, and was now in the same danger Snape had 
experienced years ago when Sirius tricked him.  So now Snape's 
motivations would change.  Could he have gone in with the intent of 
SAVING Harry, maybe as a way to repay his debt to James?  He could 
also have gone in to catch Harry breaking rules and Lupin posing 
danger to a student.  In either case, Snape would win because he'd 
come out as the hero or the upstanding teacher, while Harry and Lupin 
would be in trouble.

As an aside, I have to ask how we are able to see the invisibility 
cloak?  Does it only become invisibile when it is put on?  I recall 
that the owner of Flourish and Blotts complained about losing copies 
of the Invisible book of Invisibility.  Curious.