The monster that is inside that capsule may be "Evolsaur Diplo". This card's artwork also shows its tail being bisected.
This card's name and artwork may be based on the theory of the same name by Soviet biologist Alexander Oparin. To summarize, the Primordial Soup theory states that the archaic Earth had a chemically reducing atmosphere that was bared to different energy forms, hence producing simple organic compounds ("monomers".) These compounds accumulated in a "soup", which may have been concentrated at various locations (shorelines, oceanic vents, etc.). As these monomer compounds continued to transformation, more complex organic polymers and ultimately life, developed in the soup.
This may be reflective of not only this card's effect but the "Evol" archetype as a whole as well, as the "Evol" archetype focuses on "evolving" the "simple organic" "Evoltile"s into the "more complex organic" "Evolzar"s. By the same token, this card takes two "Evolsaur"s from the hand and "re-accumulates" them in the "primordial soup" (the Deck) so that they can hopefully "transform" into something better in the form of two drawn cards from the Deck.