system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU] What happened to Odin's spear?

Also could Thor effectively wield it or is it something only Odin benefits from?
gpt
Gungnir was likely destroyed with the rest of Asgard, as Thor never had the chance to retrieve it (and there was no real point to having Loki do so when he went back to unleash Surtur).

There was no reason Thor couldn't wield it effectively, but it wasn't a weapon he'd specifically trained with, nor was he intimately familiar with any special properties of the weapon. So when he just picked it up for fighting Hela, he wasn't as effective with it as Odin would have been in his prime. But if he had kept it, he could have learned to be as deadly with it as he was with Mjolnir.