Talk:Undyne/@comment-89.158.181.182-20151006100221/@comment-27044309-20151006105315

To spare Undyne, you have to Flee and run through the caves. You can only flee while your heart is red, however. Also, she runs faster than you, so you might have to survive a few volleys from her when she catches up with you.

Apparently, this information isn't on the page. I'll add it now.