Sweetrobin is weird.

[LynnS]

It's not his appearance that boggles, so much as his behavior.  I don't know if he's Jon Arryn's or Littlefinger's.  He is at least a Tully which means he might have some ability connected to dreaming.  He's afflicted with seizures and like Tyrion he is plagued with night terrors.  Tyrion controls it by getting drunk, so he won't remember; while Robin is given sweetsleep.  His mother is mad of course, but it's curious that Robin is afraid of men with moles. This conjures up Bloodraven and the mark on his face.  We have all the imagery of the greenseer in the Eyrie's 'throne' room - the weirwood throne, the black gate or moon door and Robin's obsession with letting the 'bad man fly'.  Not to mention the various gates and way castles (stone, snow, sky)  starting with the Bloody Gate where the knight of the gate asks "who passes".  

There might be more to Sweetrobin than just a spoiled little boy.  When he stands over Sansa's snow castle like a giant and swings his doll like a weapon busting down the walls; I'm reminded of Wun Wun swinging Ser Patrick around and busting down the walls at Castle Black.  Or Arya, whom Jon describes as swinging her dolls like a morning star when menaced by 'vegetables'.

Is it possible that Sweetrobin is being menaced in some way in his dreams or that his behavior foreshadows other events, acting out what he has seen?    Did Lysa give something away about Robin paternity when she speaks of Jon Arryn's last words about 'his' seed.  She certainly seems to think he's talking about her son.

I'm not sure we'll discover Robin's paternity discussing hair and eye color.