Door stacks, AKA "the gates of hell"

YouTube link.

YouTube link. 

The top one appears to have been modified; the second is apparently a more conventional (?) recruitment (?) video.  There is a compilation of them here, filmed with the annoying vertical format, a discussion of them at Reddit, and some explanatory notes at Atlas Obscura and at Neatorama.

I'll defer any personal commentary, since this phenomenon appears to occur in a separate reality with which I am not familiar.