You may be thinking of Sparkly Bugs, which uses the wigglyPlayer contraption from WigglyKit to set up some decorative animations by hand. The WigglyKit example deck is included with Decker as of 1.46.
A very different approach (which requires writing a little bit of code) would be to use zazz, an animation helper library, as demonstrated in this chost from last year.
I think the newer contraption-oriented approach is simpler, but zazz fits some people's brains better; use the approach that feels best to you!