Hansel and gretel is the first boss in Giana Sisters: Twisted Dreams
it appea to be a two headed worm, one head is female, the other is male.
The male head seems to be more active, being the on who makes rock fall onto giana (but you can dodge it, its kinda easy).
it also appears in the comic series.
When deafeted, it lies limb on the ground, while gems pour out of it.