Bio Planet WoO

Bio Planet WoO (生物彗星WoO Seibutsu Suisei Ū) is a "kyodai" (giant hero) themed Tokusatsu that premiered April 9, 2006, and airs at 7:30pm on NHK and ran for 13 episodes. WoO was one of many unused ideas created by Eiji Tsuburaya as a story connecting to the show Ultra Q.

The story revolves around a creature named WoO, which came from a comet. In the series, WoO is befriended by a young girl named Ai; both are chased by a mysterious organization called SWORD, which sees WoO as a threat to humanity. At the same time, giant monsters have invaded in search of WoO. The story itself follows the original script Tsuburaya intended for the show.

Tropes used in Bio Planet WoO include:

A Boy and His X - A girl and her transforming cute alien thing.
Attack of the 50-Foot Whatever - by the makers of the Ultra Series, so naturally there are bad 50 Foot Whatevers who need to be stomped by our friendly one.
Adjective Noun Fred
Baker's Dozen
Bond Creature - WoO and Ai's bond allows them to merge, making him stronger. She also feels what he's feeling even when they're separated (or at least, MIB examination upon him hurts her just as much at a distance.)
General Ripper - Yaman doesn't differentiate between good and bad alien life forms. It's revealed that his daughter was one of the victims of the aversion of Infant Immortality mentioned below.
Infant Immortality - Averted. Usually in a series like this children don't die, unless it's a Fridge Logic sorta "there had to be kids caught up in that wide-area-affecting Bad Thing" situation. However, an early Monster of the Week pulls everyone in Ai's school but Ai, who was protected by WoO, into itself. After its destruction, they - which would have to consist of a few dozen faculty and hundreds of children, do not return. A later scene shows frantic parents trying to find out what happened.
The Men in Black: SWORD.
Ridiculously Cute Critter - WoO's normal form, reminiscent of either a Zora tadpole or an In-Training Digimon Don't think that means he can't kick butt while in this form, though.
Sleep Mode Size - After exhausting his energy battling giant monsters, WoO reverts to a small, immobile "Fossil Form."