I recognize Jughead’s little head at the bottom, and Wishbone the Dog up at top left. But most of the little severed heads that dear Betty Crocker has stuck atop her totemic brownies are not ones that I know.
One of them appears to be asleep, or at least trying to block out the feeling of being watched from behind by a goofy pumpkin who has eaten too many popcorn balls.
And the one with devil horns at the back looks extremely grumpy. Try putting him on your plate! You will probably be sorry.
According to Betty, in her Party Book (1958) these are made out of lumps of hard sauce. So they will probably melt and fall off if you try and pick up a brownie. Betty was too busy rereading Gods, Graves and Scholars to remember that she had a bag of marshmallows handy, I guess.