There is a youtube video with an burned epsiode thats merged with spongebob
From The Lost Media Wiki
https://www.youtube.com/watch?v=LsyLFi-KDqY&t=108s&ab_channel=OwenFischbach this vide belongs to someone whose house got burned. He says that bunch of SpongeBob episodes and one anima from his 1980 japan visit got merged together. Around one minute mark you can hear the opening intro of the 1973 Doraemon series. at 1:14 (and onwards) you can even hear some lyrics! I unfortunately couldn figure out which episode this is from. If somone who knows Japanese gives it a shot maybe they can figure out as some of the speech can be heared.