Fedifensor
Explorer
Resilient Sphere
It's not an unusual spell in my opinion, but I never see people using resilient sphere. Any 4th level spell that can take a foe completely out of the fight with a failed save is going in my spellbook. It's even evocation, so wizards and sorcerers that love to blast everything can have a non-destructive option that takes advantage of Spell Focus and Greater Spell Focus.
It's not an unusual spell in my opinion, but I never see people using resilient sphere. Any 4th level spell that can take a foe completely out of the fight with a failed save is going in my spellbook. It's even evocation, so wizards and sorcerers that love to blast everything can have a non-destructive option that takes advantage of Spell Focus and Greater Spell Focus.