Ghastly Seraph

"The seraph was on me before I knew it, the mass of its bloated flesh soundless as it floated above the ground. When I finally noticed it, I could not move: it was as though I was trapped in a waking nightmare. I looked down and saw tendrils of energy wrapped around my feet and realized it was not fear that held me, but the seraph's magic."
— Lorath Nahr^(src)

Ghastly Seraphs (a.k.a. Vengeful Seraphs) are a type of Reaper in Diablo III. They float above the ground and have the ability to wield magic.^[1]

In-game

Seraphs are encountered all over the course of Act V, usually hiding behind their allies, but easily visible because of their abnormally bloated bodies. They have just one attack: a ball of ice that deals average Cold damage. Occasionally, the Seraph will create a patch of ice extending roughly 60 yards in front of him, which Chills any enemy on it (if the player is standing right next to Seraph, they are also knocked back a bit). Once the patch is created, the Seraph will immediately launch an iceball through it.

Seraphs are most dangerous when assisted by Punishers or Executioners, as their ice patches can slow the player down and make them more vulnerable to stunlock of these foes.