Lance of Annihilation

The Lance of Annihilation is a classical spell of last resort. Invented by a wizardess of Jovirenia, the spell contains the usual purple tint characteristic of most of the magic from that country.
The intention behind the Lance of Annihilation is to be used during desperate sieges and attacks, where the only hope of victory comes from the particular magician putting their last bit of energy into the spell. When all other avenues have been lost, the magician can use this spell, which creates a massive bolt of what appears to be purple lightning but is in fact pure arcane power, and then blasts whatever the target may be.
This spell is infallible. It does not fail to miss, because it depends fully on mental energy and focus, and it is destructive enough that even were it to specifically miss some pinpoint target, it would hit close enough that it would not matter. Science and magic alike have yet to find something that can't be destroyed by this spell.
The spell is also lethal to the caster. It expends every last bit of magical energy the person possesses, and since it is meant to come after a long battle, they won't have much left. It is considered something of a faux pas to survive casting the Lance of Annihilation, actually. If you survived, that means you probably had a lot of other options yet. Besides, even at full strength, most magicians don't have enough in them to cast this without giving their lives.
In some circles, the spell is considered a bit spiteful, as its main use is to utterly smite something without actually surviving to victory yourself. Still, our world is such that this is considered entertaining so the spell is entirely legal.

Material Components

Just the magician is needed. The point of the spell is that it is a last resort, something to do only after you have exhausted all logical recourse, all supplies you maybe have brought into the battle, all the rituals you had prepared. All that is needed is internal energy.

Gestures & Ritual

The incantation is not one that I will repeat here, in part because no one wants any idiot to accidentally unleash it. It is rather simple, actually. The Lance requires more mental preparation than anything, a kind of mental checking of the boxes that yes, you do intend to do this, and that is the target, and we're really doing this. I'm told that most people believe a certain amount of spite and anger is needed to truly charge the spell. Gather the energy within, utter the spell words, and release. Quite simple.

Effect Casting Time

1 minute, plus however much time the magician takes to decide to perform this probably lethal spell