Yes. This happened in Season 23.
There have been references to SpongeBob in The Simpsons episodes and the character appears in several Simpsons episodes. SpongeBob is also referenced in a couple of Simpsons comics.There are also a couple of references to The Simpsons in SpongeBob SquarePants episodes.
None, the Simpsons as a series didn't air on T.V. until 1989
According to Simpsons Wiki, In 25 Seasons, she's appeared in 56 episodes
409
24 Minutes
he sould be back in the second simpsons movie.i really want him to be i another simpsons episodes
234 episodes aired during that decade.
youtube
21
25
23 so far
Because Pokemon episodes take less time to produce, plus from what I can find online, the episodes are made & air year round with a few breaks here & there. The Simpsons however only airs new episodes from September to May & only 20 to 23 episodes air each television season.