The kraken doesn't seem to be very discriminating. After all, the first boat we see it destroy was simply in possession of Jack's hat.
The Top 214 All-Time Leaders for Biggest Drop In Second Weekend Box Office as Percentage of First Weekend Box Office.
#1 for a movie that made more than $50 million its first weekend is
Hulk (40th overall) which dropped 70% the next weekend. That is powerfully bad word of mouth. #2 (72nd overall) for films over $50 million is
X-Men: The Last Stand which dropped 66%. #3 (132nd) is
2 Fast 2 Furious. #4 (140th) is
Harry Potter and the Prisoner of Azkaban.
If you're watching the box office game is that
PotC
CM will probably pass
Superman Returns in overall box office after today doing in 4 days what that movie did in 12.
Superman's 58% second-weekend drop will not get it onto the list above.