particle find target & lock target in a uniform way

[genzyanz]

Hi I am a begginer in a particle system. I have a scene where I want a particle to morph into an organic matter such as an octopus.

I used find target and lock target in particle viewer. It work fine but I don't like the way it transform. the particle seems like exploading randomly and instantly morph into an octopus as a whole.

I want the animation to be started at octopus head and each tentacles will grow like a tree root one by one. But the find target and lock target morph my mesh instanteaneously at once.

Please let me know how to do it right or how I am going to morph my mesh in a uniform way. not at onces


Thanks in advance