Alrighty, Buddy, I Need You to Make a Constitution Saving Throw

Buddy, I'm going to crash and do shatter right across the poor buddy's head. You take four D-eight thunder damage. So you moved up close to buddy, are you going to move back or stay right there in the fray? No, I'll jog back. All righty, finishing back, she's about... How far away is she? What's your movement? I'm a dwarf, twenty-five feet. Twenty points of hundred damage to you, buddy.