You might want to avoid using the Spear in Helldivers 2 for the foreseeable future, because it's crashing the entire game under certain circumstances.
Earlier today, a Helldivers 2 player directly asked Arrowhead in the third-person shooter's Discord whether they were looking into crashes when using the Spear Stratagem. Specifically, the player wrote that the entire game crashed whenever they locked onto an enemy using the Spear, which is pretty concerning for the entire game at large.
Representing Arrowhead, community manager Twinbeard responded to the Discord user, seen in the screenshot just below. The developer reveals that Arrowhead is very much aware of crashes related to the Spear Stratagem under certain circumstances, and adds that "we're looking into it!"
To all helldivers: Please avoid using FAF14-Spear at this moment from r/Helldivers
It's a relief to know that Arrowhead is actively looking into whatever's causing the crashes surrounding the Spear. For the time being, though, we'd highly recommend not using the Spear whatsoever in Helldivers 2, since we don't know what's actually causing the crash relating to the Stratagem.
Proof of this is one Reddit comment underneath the screenshot post, where a player writes that they've been using the Spear without an issue recently, but that they routinely see people from their squad drop out mid-game. They theorize that this could be due to the Spear crashing their squadmate's games, which is plausible, but odd that the weapon wouldn't crash their game as well.
Others have had worse experiences with the Spear. The player just below, for example, claims the Spear has sent them crashing out of Helldivers 2 simply for having it on them, even if they weren't aiming it. Commenters claim to have the crash occur on both Automaton and Terminid-based missions, so right now, there's no obvious commonality for what's causing the crashes.
Spear will crash you to the desktop from r/Helldivers