League-of-legends – Can you QuickSilver Sash or Cleanse out of Poppy’s Ultimate

Skarner can't flash while ulting someone; the ability icon greys out

Other moving effects, like ghost or an enemy push/pull will drag your victim along for the ride, though.

All displacement type spells (knock-back, knock-up, pulls, etc) cannot be prevented or ended by the use of Cleanse. Additionally, these type of spells are not affected by Tenacity. The only other form of Crowd Control that is not effected by tenacity or cleanse is Suppression, such as Warwick and Malzahar's ultimates.

However, it is worth noting that there are ways to prevent these types of spells, such as Sivir or Nocturn's shield, Morgana's Black shield, or Banshee's veil.

A lot of information about the varying effects and counters of Crowd Control types can be found here: http://leagueoflegends.wikia.com/wiki/Crowd_control