When I was sneaking through that area with the barb-wire, I encounted a mysterious frog doll with a big smilie face. I tried to pick it up, I tried to shoot it (and caught the attention of a guard), and I tried to stare it down!

What was the purpose of that thing?

there are 64 ( i beleive ) of these "keroten" frogs, shoot them all befor the end of the game , and u get ths stealth camo, this is an alternative, to the tschuniko (or w/e its called) snake or the no alerts and what not...

the tuschino gives you infinity facepaint not stealth camo

Check a guide to see all unlockable items and other stuffs in the game.

Also Tsuchinoko gives you infinity face paint after you've brought it ALIVE until the mission ends.

Just get 0 continues 0 alerts and you will get the stealth camo. It will take you around 10-15 hours of game play. Its really not much. DONT GO AFTER THE STUPID FROGS TAKES TOO LONG AND IF YOU MISS JUST 1 YOUR SCREWED!!!!! happen to me once
HERE is the rating you will most likley get if you do what i said.
*********NOTE: the following is the list of requirements to get the stealth camo and the rank of "Chameleon" this is froma FAQ wriiten by lionhart627 ALL credit is given to him, if you are interested in his ULTIMATE i mean ULLTIMATE FAQ for MGS3 just post and i will tell you where to go ***************

+-----------+
| Chameleon |
+-----------+

Play Time : N/A
Difficulty : N/A
Number of Alerts : 0
Continues : 0
Kills : N/A
Meals : N/A
Saves : N/A
Life Medicines : N/A
Damage Received : N/A
Special Item : N/A
Extra Info : N/A
Reward : Stealth Camouflage

All the frogs you've got will be counted even if you repeat the game, you don't need to shoot them again. The only thing matters is that the frogs you've missed.

its still a real b@#$% trying to keep track of all the ones that youve already hit, and some of them are really hard to find or hit, like the ones on the motorcycle chase levels