Kaa is a large Indian Python who appeared in Rudyard Kipling's 1894 anthology The Jungle Book. He plays a major role in the segment "Kaa's Hunting", in which he aids in the rescue of Mowgli from the Bandar-Log (a group of grey langurs) and devours the kidnappers after subduing them with a hypnotic dance. In certain adaptations, he is put in a villainous role in which he attempts to consume Mowgli whenever he thinks no one's looking.
Created by CatsTuxedo on Jul 22 2010
Special thanks to TylerMirage, Bry for additional sound clips.
In terms of Disney's adaptation of the character, Holloway and Cummings get the creepy aspect of the character down-pat, but Holloway's performance seems a bit more menacing. Cummings' performance has some traces of "Winnie-the-Pooh" in it (especially when he giggles), which causes him to lose some of his edge. Johansson isn't quite as distinctive as far as sound goes, but her sultry and deceptively soothing delivery compliments the character well enough. As for the rare case of Kaa as a heroic character, Elliott is an outside-the-box choice that certainly paid off; his low, creaky delivery fits Kaa quite well, and he's capable of sounding either wise or menacing depending on what the scene called for.
I'm calling a tie between Holloway and Elliot for their respective versions of the character.