It's all nonsense, of course, but presented as fact (along with "specimens" of many other cryptids.) Seems that it is, in fact, a very imaginative art project by talented sculptor and cryptid enthusiast "Alex CF." Interesting read, and intricately created pieces of many different cryptids. Don't think many cryptozoologists would consider the obviously fictitious elder things and cthulu spawn as real as Nessie, but it's a fun pretense.
http://www.merrylinmuseum.com/index/#/expedition-to-the-elder-city/
http://www.merrylinmuseum.com/index/#/eldritch-study-bureau/