Smart as a tack

This is an example of a perfectly formed malaphor.  It is a congruent conflation (the best kind of malaphor, imho) of “smart as a whip” and “sharp as a tack”, both describing someone as highly intelligent.  Smart and sharp are similar sounding words, and both idioms contain the “as a” words.  Also, if you sit on a tack, it does smart, doesn’t it?  The mashup is also heard in the Adam Sandler movie, “Big Daddy”.  Here’s the clip:

A big thanks to Martin Pietrucha who heard this one and sent it in.