Soup, made by Ultramarines.
Сontext:
For russian and/or other slavic language speakers lyrics of Ultramarines Chant "Agitatis Ultramarini! Dominitis Ultramarini! Non Praestatis Ultramarini! Nobilitis Ultramarini!" sound weirdly similar to words "Горячий суп наварили! О, великий суп наварили! О, шикарный суп наварили! О, великий суп наварили!", meaning "Hot soup has been made! Oh, great soup has been made! Oh, gorgeous soup has been made! Oh, great soup has been made!"
A funny coincidence resulted in creation of a meme so popular, it eventually overtook the original song in views on YouTube and subsequently became a staple of russian Warhammer 40k community, spawning derivative memes, such as "soup-cookers/soup-brewers" (суповары) nickname for Ultramarines.
What are those Ultramarines doing? They're making great soup.