Years ago I was playing Yuri's Revenge mission "Romanov on the run". While playing this mission, I noticed a huge pack of polar bears coming off the map from the north direction. I knew I was witnessing a secret. However I was never able to reproduce that secret. Years have passed and I've decided to come back to this topic. My first attempts of trying to produce that secret failed. Untill I finally looked into Final Alert editor and discovered there are special triggers. It appears one unit has to be exactly in a specific spot (in the attached picture, it's the halftrack in the middle of screen), wait there a moment and this will trigger the polar bears! Those teddies will shape the word "HI". It's kinda a funny secret and I am astonished how this one was out of the radar for so long. Yes, I've been trying to search everywhere whether there was any other person who found it, but I had no luck.
Ohh and these teddies are controllable :D.