What does "なにしに" mean?


I've just begun reading the Doraemon manga. Coming across this phrase, I've
searched for its meaning but have been unable to find anything helpful so far.
An English translation of the manga suggests the phrase might mean "what are
you here for?", which certainly fits the context, and of course "なに" I am
familiar with. However, I do not understand what role "しに" plays, as this
seems to only directly translate as "death".

[![enter image description
here](https://i.stack.imgur.com/nRmUw.jpg)](https://i.stack.imgur.com/nRmUw.jpg)




It's a truncated 何をしに来たんだ？ (What did you come here for?)

With the back half cut off and the particle を omitted, it becomes なにしに




It's a truncated 何をしに来たんだ？ (What did you come here for?)

With the back half cut off and the particle を omitted, it becomes なにしに

