"H" white speedy object, half-turned then vanished, 11 frames only

recorded at: August 12, 2017 Trifouillax agel 151 18

Capture that thing yesterday evening, white stuff (local birds are globally black), "H" shape (or inverted "Z"), spot turned then vanished suddenly between frame 11 and 12.

What do you think?

Good skies,

jm (France)