Create a simple Jello Effect in Nuke. It is basically just a lens distortion node with auto scaling functionality.

CS_JelloEffect.tcl

set cut_paste_input [stack 0]
version 9.0 v5
push $cut_paste_input
Group {
 name CS_JelloEffect1
 selected true
 xpos -2900
 ypos 1166
 addUserKnob {20 CS_JelloEffect}
 addUserKnob {7 effect R -1 1}
 addUserKnob {14 minScale R 0 100}
 minScale 0.9
 addUserKnob {14 maxScale -STARTLINE R 0 100}
 maxScale 1.31
}
 Input {
  inputs 0
  name Input
  xpos -590
  ypos 302
 }
 LensDistortion {
  serializeKnob ""
  serialiseKnob "22 serialization::archive 9 0 0 0 0 0 0 0 0 0 0 0 0"
  distortion1 {{"parent.effect * 0.3"}}
  filter Keys
  cardScale {1.06850183 1.06850183 1}
  a -0.02740807459
  b -0.02840842493
  c -0.01126380544
  name LensDistortion1
  xpos -590
  ypos 374
 }
 Transform {
  scale {{"1 + (parent.effect < 0 ? pow(-parent.effect, 1 / 1.25) * (parent.maxScale - 1) : parent.effect * (parent.minScale - 1))"} {"1 + (parent.effect < 0 ? pow(-parent.effect, 1 / 1.25) * (parent.maxScale - 1) : parent.effect * (parent.minScale - 1))"}}
  center {960 540}
  filter Keys
  name Transform1
  xpos -590
  ypos 400
 }
 Output {
  name Output
  xpos -590
  ypos 470
 }
end_group