Indicator for sell off / buy up

[Frank]

Hey,

i am looking for an indicator that identifies an selloff/buyup.

For my strategie it should draw a line in the end of the sell off/buy up. But this is the second point.

Is there a indicator out there what identifies this?

On the other side, if not .....

How can it be possible for an indicator to identify it? Did you have an idea of the needed math?

A little Brainstorming will be welcome

Thx, Frank