The "mimic" type of monster has seen an upsurge in popularity recently. Most typically disguising itself as a treasure chest, the mimic might also be a chair, a doorknob . . . or anything else that some unwary delver might touch.
So who thought of this evil beastie?
I just ran across a story that might depict the original fictional Mimic. It's "The Stentorii Luggage," by Neal Barrett, Jr. – and it appeared in Galaxy Magazine in 1960! So Barrett may have intellectual priority on the idea. And, regardless, it is a great story.