ToonClix was planned to be an expansion to grow the Clix Empire. It was a collectible miniatures game aimed more specifically at the 6-12 year old demographic, with nostalgia characters aimed at older and (presumably) existing Heroclix collectors. From the original article reporting on it from March 2006:

ToonClix will feature figures based on cartoon characters from the libraries of Warner Bros. (Looney Tunes), the Cartoon Network, Hanna Barbera, and the Kids’ WB. With only 36 figures in the first set ToonClix should be easy to collect and players will find enough to play a game in every pack. The goal of the game is to get your character to the highest state of happiness, and each figure will come with cards that can be used to create a diorama-like background.

DC HeroClix: Arkham Asylum
Designer’s Notebook: HeroClix Map Design
by Seth Johnson, Arkham Asylum Lead Designer

Quoted from the original Press Release (with help from the Internet Archive’s WayBackMachine):

Quoted from the original Press Release (with help from the Internet Archive’s WayBackMachine):

JUNE 23, 2003 (SEATTLE) — Today, The Topps Company, the trading card, collectibles, and confectionary company, announced it is acquiring WizKids, Inc (“WizKids”), a privately held designer and marketer of collectible strategy games, headquartered in Bellevue, Washington. WizKids’ current games include Mage Knight, HeroClix, and MechWarrior, all of which utilize collectible miniature figures with a patent-pending “combat dial” that encodes relevant game information in the base of each piece.

The History of Clix for the Cure

SEATTLE, WA – February 1, 2002 – WizKids, Inc is proud to announce their new collectable miniatures game, Marvel HeroClix: Infinity Challenge will be available nationwide beginning May 1, 2002 to coincide with the release of the Spider-Man motion picture.