This is coming from memory for I am at work and thus have no books at hand.
Instant Charging Bull of Foe Propellation (better name suggestions accepted)
CrAn(Re) 20 (Base 10, +1 touch, +1 requisite)
R: Touch, D: Momentary, T: Individual
The magus creates a charging Ox right in front of him which bullrushes forward headbutting and trampling anyone and anything in front of it. The Ox persists for a few seconds and then fades away like smooke in to the wind.
Magus Aloysius created this spell when he realized he needed to get out of tight spots.
Actually, the spell was supposed to basically knock people out of the way quickly to enable the magus to escape tight situations, such as cornering. It was never supposed to a real cause-havoc-spell as such.
With Aloysius being a slow caster and all, he needed some quick get-away spell to be invested into a magic device, but I guess I should think of another one. And, yes, Aloysius is an Animál specialist.
In previous sagas we had an Animal expert create a similar spell at momentary. In 5th I'd certainly allow it, mostly because of the new Penetration rules.
You're assuming that the bull is suffering from summoning sickness. I was assuming, from the spell description, that the bull is conjured already at full speed. That's why there's a rego requisite.
Is there some reason why the bulll needs to be summoned at velocity 0 and then accelerated?
Fires are not normally known for their velocity yet you used a fireball as your example. If you don't have a problem with Mighty Torrent of Water or Ball of Abyssal Flame why do you have difficulty with this spell?
How long the is a moment, pray tell? I would rather think it a "blink" should it last for less than a second but you are entitled to your opinion. A moment is more than a blink but less than a while. Hmm.
You people seem to think that the Momentary duration is something similar to one frame in a computer game or something... I'd rather think that a Momentary spell can do just one thing and the momentary duration lasts just long enough for the spell to take it's effect, say the bull rush over the enemy and then dissipate, or the fireball to fly in the face of your foe and then disappear.
But then again, this is the matter of choice, so I say SGs are free to make their own interpretation of this rule.