There was a bug that went out with our 3.2 update that allowed incorrect targeting of troops spells. As a result certain troops were able to target enemies with spells that should only have been targeting Allies (Elspeth, Sacrificial Priest, and Black Beast). As such we’ve made some temporary changes to these troops until we can get a more permanent fix out for the bug as a whole. As of now the three troops, Elspeth, Sacrificial Priest, and Black Beast will target the last Ally in the team with their spell, rather than letting the player choose the target. This does mean that if the caster is the last troop in the team, that they will target themself. And while Elspeth and Sacrificial Priest have always been able to target themselves, Black Beast has not. So be aware that if Black Beast is in last position in the team when you cast his spell, he will eat himself to death!
EDIT: We’ve updated Elspeth again. She now allows a target for Gem Creation, but will still always sacrifice the last Ally troop.