What happened to my baby?

[fuzzyeye]

It is acting weird It is stuck in this strange animation 





And it dies.

 

[iAM]

Not sure what is it exactly but you said it died so probably that is one of its death animations! 

 

[fuzzyeye]

While it is doing that any button will kill it.

here is the death animation







Maybe it might be having a seizure.

 

[Eggiweg]

Yup, this just means that your gudetama has died and has been "cooked".

Certain conditions will give you certain egg dishes.  Here is an incomplete list of the dishes you can get https://tamagotchi.fandom.com/wiki/Gudetama_Tamagotchi/Character_list