there are many techniques involved here and probably no scripts or plugins just pure timing of keyframes. for the bubbles you can use several Ae native effects like the ones under simulation category: Foam, and the particle effects.
for timing you could cleverly use the graph editor to make nice speed changes: https://vimeo.com/68022971
which part exactly do you find difficult to execute?
Roei Tzoref
2D/VFX Generalist & Instructor
♫ AeBlues Tutorials ♫
http://www.tzoref.com
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