Anyway, the other day I was piddling around in Flash trying to make tsunami effect w/o following lenthgy suggested tutorials, and I found a way that's is a bit glitchy, but still works.
I was messing around with stuff for my home site just out of boredom, anyway, here it is
moosboy is an mc that follows the mouse which cover all the screen for the first second or so, then stop and decrease it's size to about W:164.8 H:doesn't matter as long as it can touch the mc's you want to change size.