frog muppet + instrument = keromin
You put your hand to control the mouth. How wide the mouth opened determines the pitch (the wider, the higher). And, press/hold a button on the back to play the voice. You can change the scales (all major/minor scales, and some ethnic/folk/blues scales). They have MIDI and line outs, too.
Please note that the center frog in the above video is not a keromin. This video is a fan contributed one and he wrapped some sort of small theremin in keromin-like frog muppet.
This cute instrument was featured in the 2012 Ig novel ceremony at MIT. Seek to about 30 min.
Evolution of keromin (keromine, kokeromine, kokeromine lime)
I found a table comparing between keromine and kokeromine. But the page is in Japanese. So, I will give you a short summary here:
Kerominis the first generation and the most expensive model (about 520 USD) for a serious musician. Keromin has a powerful speaker, a dip switch panel for detailed settings, and a wide octave range 2C to 7C.
Kokeromin is a more affordable version of keromine (about 100 USD) with some updates in the software side (more ethnic scales etc) for casual hobbyists. There are some compromises for build quality and scale range (at low pitch about half an octave less), speaker power, etc.
Recently, Kokeromin lime is announced and soon to be released (2013 spring). They are taking pre-order requests (see below). This is a cheaper (70 USD) version of kokeromin yet it offers some nice new functions such as vowel singing mode (a, i, u, e, o) and drum set voicing functions.
Wow! Kokeromin lime can sing a song! Vowel singing mode
Check this youtube video singing "Happy Birthday", demonstrating the vowel singing mode. OMG, can you believe that he is only singing with vowel!? So, in stead of "happy birthday to you", he is actually singing as "a i, a u e u u".
It's so cute and affordable (70 USD) and offers so much fun. Kokeromin lite is the model I am gonna have to buy!!!
How to buy? Do they ship oversea?
Yes, they do! They are happy to accept orders from oversea. You can email them (kaeru(atmark)keromin.com) and check the details! Plz remember the kokeromin lime is not released as of writing.