SpongeBob SquarePants/Mario

Version 1

 * Spongebob as Mario
 * Squidward as Luigi
 * Patrick as Yoshi
 * Sandy as Peach
 * Pearl as Daisy
 * Mindy as Birdo
 * Gary as Toad
 * Snellie as Toadette
 * Fred as Para Koopa
 * Mrs. Puff as Rosalina
 * Mr. Krabs as Donkey Kong
 * Spongebob's Grandpa as Toadsworth
 * Larry as Wario
 * Squilliam as Waluigi
 * Stanley S. SquarePants as Mallow
 * Plankton as Bowser
 * Karen as Wendy O. Koopa

Version 2

 * Spongebob as Mario
 * Patrick as Luigi (but squidward is not luigi) (no squidward is bad and luigi is good)
 * Gary as Yoshi
 * Pearl as Peach (Pearl and Peach both have names starting with 'P')
 * Sandy as Daisy (Sandy and Daisy both have names ending with 'Y')
 * Mindy as Birdo
 * Stanley as Toad
 * Mr Krabs as Wario (Mr Krabs and Wario are both greedy)
 * Squidward as Oogtar
 * Squilliam as Waluigi
 * Karen as R.O.B
 * Larry as Donkey Kong (Larry and Donkey Kong are both strong)
 * Plankton as Bowser (Plankton and Bowser are both villains)

Version 3

 * Spongebob as Mario
 * Patrick as Luigi
 * Squidward as Yoshi
 * Sandy as Princess Peach (Sandy and Peach are both girlfriends to Spongebob and Mario)
 * Mindy as Princess Daisy (Mindy and Daisy are both girlfriends to Patrick and Luigi)
 * Pearl as Birdo
 * Mr. Krabs as Oogtar
 * Larry as Donkey Kong
 * Mrs. Puff as Candy Kong
 * Gary as Toad
 * Plankton as Bowser
 * Karen as Wendy O. Koopa
 * and more

Version 4

 * Spongebob as Mario
 * Stanley as Luigi (Stanley & Luigi are both related to Spongebob & Mario)
 * Patrick as Yoshi
 * Sandy as Princess Peach (Sandy and Peach are both girlfriends to Spongebob and Mario)
 * Pearl as Princess Daisy
 * Mr. Krabs as Toadsworth
 * Gary as Toad
 * Mrs. Puff as Rosalina
 * Plankton as Bowser
 * Mindy as Birdo
 * Squidward as Wario
 * Squiliam as Waluigi