Insect swarm

I'm noob with pflow and wanted some advices on how to set up a job.
I have to realize a swarm of insects that initially has the shape of a classical cloud of moving insects then attacks an object and wraps it as a "tentacle".

First step - how to make enough of organic forms in motion as in the attached pictures? it is best to do the simulations in FumeFX and then assign the behavior to the particles in pflow, or is there a better way without using FumeFX?

Second step - when the swarm becomes a "tentacle", the best thing is to drive the particles with a find target that moves along a curvy spline? I can get something like that or I need some script?

can someone help me?