James Gunn Hints at New Monster in Latest Guardians of the Galaxy Vol. 2 Concept Art
The team is definitely going crazy on some sort of twisted giant space squid monster here. The picture is a bit reminscent of the 'Old God's' from the Cancerverse -- an alternate reality with its first appearance in the Marvel Cosmic corner of comic book universe:
All I know for sure here, is you've gotta love Baby Groot!