I am currently new to shadowrun and I am playing a combat mage. I cast manaball at a group of enemies and my friends I were wondering what would this spell look like? I know I don't have to do anything but look and concentrate at them for the spell to be cast but would something from me be shot towards them or is there something invisible that hits them and they scream to death?
Is this the same for most spells? I bet that elemental spells come out to be elemental but what about health, illusion and manipulation spells?
If they are invisible and I cast a manaball in a bar to kill a bunch of guys sitting at a table, would people realize that i was the one that cast it?

thanks

The short answer is that your spells look like whatever you want them to look like.

The slightly longer answer is that in previous editions to SR, there was a Perception Test TN based on the Force of the spell for people to notice it being cast. (I think it was 10-Force, but it's been awhile.) SR4 might have a similar rule, might not, but I'm too lazy to look it up right now.

i think in sr4 the test is threshold 6 minus force, but dont quote me on it.