Yep, thats what it always looks like when its at full activity. Mesmerizing isn't it? Thats normal behavior for repitching onto a cake. Basically, when you pitch a normal starter, you still have yeast growth going on, the beasties come from an o2 rich environment, so they grow till the o2 is gone, then they switch to eating mode. The yeasties in the cake were already in eating mode, and not in growing mode. You just dumped a huge buffet table full of food in front of a starving army.
