How do you think of enemies, bosses and items to put into The Binding of Isaac? Do you do it from the top down (think of a concept, and then translate that into Isaac) or from the bottom up (think of an item, then think of 'fluff' to justify it? A Lithopedion would be a cool thing to see in Rebirth

I tend to think of enemies and bosses top down, usually coming up with a child deformity, demon or other abomination and designing around how it looks.

with items though its def. a bottom up design. i always think up the effect 1st then design the item around what it does, because its usually more important to the games design than an enemy or boss. 

and yes, a stone baby was something i played with in isaac, the stone heads were going to be stone babies but they just looked weird…