That is the dilemma! The fool didn't even use a pentacle, which is a fine detail that is going to bite him in the bottom. Quite literally, when I find the offending magician, and I intend to do it with a grin (if I can form proper teeth in time).

[Have some more oozing and sloshing noises, kind of like the blob is dancing, because he cannot wait to find the silly magician who summoned him without a pentacle. That is-- well, it's impossible, but it leaves the magician as vulnerable as if he knew one's birthname (looking at you, Mandrake).]