hi :3 i got a weird game over screen on switch and i couldnt find anyone else talking about it! i posted a vid on my bsky here!
it happened while i was trying to back track to the shop with the pink key (i was super lost lol). i ran into the flower enemy and had like no hp so i was defeated, then you can see in the video that i pressed continue and the dog showed up instead of booting me back in. i had to restart the game to keep playing.
It's a bug. that screen is the dogcheck for chapter 5, which shows up when loading a corrupted save file. Some of the events that triggered them just by playing have been and will be addressed when playing, but updates for console versions will take longer to come out.
The reload glitched and sent you into an invalid room. When this happens, the game then sends you to this room, the “dogcheck room” when playing chapter five. Each chapter has its own dogcheck room, and Undertale has two, of which one is randomly selected when attempting to load an invalid room.