Projectiles?

[Hellz Meteor]

What kind of method or function should I look at to create a projectile that will do something to a player once it touches them?

I am really new to GS2, and I couldn't figure it out in GS1 either, so basic instruction would be best.

for example, Player1 Shoots a projectile that moves in a straight line. Player 2 gets hit by it and says "Im hit!"


Thanks in advance.