[Seeing the doll back up makes Undyne actually calm down for a second. Her gestures are very similar to the few and far between monsters who're actually scared of Undyne's strength, like Whimsun. But her confidence seems to shoot back up upon hearing that last comment.]

"Me? Succumb? I'm the captain of the Royal Guard!" [She summons another spear confidently.] "I'll show you true strength..." [And she's about to lob the spear at another Nexus furniture object, but finds her hand shaking violently. The weapon drops to the floor and disappears, causing Undyne to laugh weakly.]

"Huh...Damnit...I didn't think the kid actually did that much damage to me."