How about an offensive affliction spell, similar to Fear, that causes the target to experience intense, euphoric joy, making them incapable of movement, attack, or defense? They would just stand there swaying slightly like they're stunned, for about...I don't know...5-12 seconds. They'd die in bliss.
I mean, think about all the nasty spells we have. Acid, cold, fire, fear, madness...what horrible ways to die.
But while at it, why not a spell that is called Viagra, where the subject stands stiffened, rock hard. Unable to move but cant be harmed either. Great solution for adds. Oh, and he looses stamina while Viagra'd...
... An lets not leave out the Drunk spell, target ambles around without meaning, doing random emotes, wakes up with headache, loss of hp, stam and focus, specially focus...
( i mean, we have the berserker stanza, that according to legend was achieved by drinking a rather nasty mix of mjød, a selection of herbs and certain muchrooms )
... or the Infatuation spell, targets is unable to do anything coherently and follows you around star eyed, losing sap all the while....
... or the Impotence spell, the opposite of the Viagra spell, you go totally rubbery, can only be cured by a Viagra spell of the same level...
... the AoE Fan spell, target is immediately accosted by all monsters in a radius, that will just congregate on the victim and not allow him to move...
... or the Bodybuilder spell were the target takes of his armor and just stands doing poses...