Baby Grows Up Doll was made by Mattel in the 70's. She would grow in the legs about two inches when you pulled her string. She came with two outfits. She had a pink outfit with a bonnet when she was small and a blue check one when she grew.
I remember how when I played with Baby Grows Up Doll it felt like I had two dolls in one!
The doll came packed up in a yellow box with pictures of the two versions of the doll on the front. To hopefully avoid any confusion, instructions on the box carefully detailed how you converted the doll from a small baby to a toddler:
"The doll comes as a little girl. To make her a baby, pull the baby ring on her back, then put on her baby clothes. You can play with her as a baby as long as you like. If you want her to grow up, just feed her her bottle. When she's finished, and you remove the bottle, she'll grow up. Now she's your little girl. So you can take off her bonnet and baby clothes, let her hair down, and put on her pretty little girl dress and shoes."