Oh, I know exactly what you mean, but it's a nightmare to put into words.
However it would be more like:
Dum, dum, dum, dum daaaaaaaaaahhhh! Da-da-da-da (and repeat)
where the daaaaaaaaaahhhh is a trill. In terms of timing, the Dums are a beat each, daaaaaaaaaahhhh is 2 and the da-da-da-da are two.
The dums do ascend but they're ponderous, like someone is trying to walk on tiptoes round a haunted house. It's the sort of thing that you might hear in Scooby Doo or Abbot and Costello Meet The Mummy but it's got the same sort of ubiquity as 'Entry of the Gladiators' has for clowns.
Sorry I can't be more helpful than that, but I do know exactly what you mean!