What is "monstration"

Monstration \Mon*stra"tion\, n. [L. monstratio.] The act of demonstrating; proof. [Obs.]

A certain monstration.
--Grafton.

n. 1 (context obsolete English) The act of demonstrate; proof. 2 a flash-mob popular in Russia, where young people take to the streets homemade banners and placards sporting absurd, non-political, funny slogans.

A monstration is a public performance similar to a demonstration, but intended as creative performance art, often parodying a serious demonstration. It is principally a Russian phenomenon.