OH MY GOD DON'T JUST THROW AWAY A PERFECTLY GOOD SPEAR LIKE THAT!! You could have hit someone! [Undyne says this with the firm conviction of someone who has definitely thrown a shitton of spears into the distance before without bothering to see if anyone might be in the way.]

So that's how you wanna play it? Fine! Don't say I didn't warn ya! NGAAAAAAAAAAAAAAH! [She starts running towards him, bringing her arm back to hurl her spear hard and fast at where he's standing. Immediately after it leaves her hand, she summons another one and sends it flying at him too.]