Toon World

Toon World is both a location and object in the Yu-Gi-Oh! franchise. In the anime, it is a dangerous Spell-Card and favorite card utilized by Maximillion J. Pegasus, which allows him to transform regular monsters into Toon monsters.

Appearance
Toon World appears as a large children's pop-up book. It's bindings are green and has a picture of Manga Ryu-Ran on the front with the words "TOON WORLD" above him in Rainbow colored font, and another picture of Toon Mermaid on the back. When opened, it reveals a Gothic-style city with dark buildings and headstones, but with wackier shapes and sizes.

Powers and weaknesses
Toon World is an extremely powerful Spell Card that has the power to create Toon monsters, which are comical, but sinister counterparts of already existing monsters. These Toons have all the power and abilities that their original forms have, but with a twist; due to their sheer cleverness, they cannot be destroyed in battle by non-Toon monsters, and they can sneak past non-Toons and attack the opponent directly. This style of battling makes Toon World a force to be reckoned with.

But these Toons have a severe weakness; Toon World is the source of their existence, and if it were ever destroyed, they would be destroyed along with it. Also, utilizing a Toon deck has its price, as the user must give up lifepoints to activate Toon World or attack with their Toon monsters.

Past
Maximillion J. Pegasus's childhood consisted of watching cartoons, most notably a series known as Funny Bunny, in which the titular character constantly outwitted a canine law enforcer, Ruff Ruff McDogg. Inspired by the rabbits hilarious antics and cleverness, Pegasus created Toon World as a means of allowing his monsters to replicate the same cleverness, thus making them nigh-unstoppable.

Champion vs. Creator Part 2
Pegasus first used this card against Seto Kaiba, who had already began struggling against him due to his cheating with the Millennium Eye. First, he used this card to seal away his Dark Rabbit, keeping him safe. On his next turn, Pegasus then summoned the Blue-Eyes White Dragon he stole from Kaiba in the previous episode. Then he used Toon World to transform the legendary dragon into the giggling and seemingly insane Blue-Eyes Toon Dragon, which repulsed Kaiba. Then Kaiba summoned another Blue-Eyes from his deck and attempted to destroy the Blue-Eyes Toon with it, but it stretched out of the way, thus showcasing the true power of Toon World. Pegasus then used a Spell Card to power up his Toon Dragon and Kaiba's monster, but Seto activates a Trap Card to save his Blue-Eyes. Kaiba then uses his own Spell Card to shackle the Blue-Eyes Toon and decrease its power, allowing his Blue-Eyes to finish it off.

However, Pegasus then captured Kaiba's Blue-Eyes and threaten to turn it into another Toon like the first one. Kaiba attempted to save it, but Pegasus activates a card called Doppelganger that can copy any other card, and has it copy Kaiba's Crush Card Virus, causing all Seto's cards to become infected and useless. All Kaiba could do was revive his weakest monster, Saggi the Dark Clown, and Pegasus finished him off with his Bickuribox, winning the duel and Kaiba's soul in the process.