A large magnet is fired, which spawns many other magnets in a V formation when it hits the ground. The sides of the V reverse by the time they all hit the ground.
There is no initial projectile -- instead, lots of small magnets slowly fall and are attracted to the tanks on the battlefield. They tend to target tanks that are higher up. Most effective when only one enemy is left.
Magnets usually does 56 damage on a single enemy (not counting crits) if aimed directly on target. However, it is possible to do 98 damage (not counting crits) if the target is at the bottom of the map and the weapon hits slightly to the left or right of the target (check attached video).
It does not matter how you aim Attractoids; the shot will always be the same, since it's a Smart weapon.
Very few projectiles will hit enemy tanks if Attractoids is used with high wind. It is recommended that this weapon only be used when there is ~5 wind or lower.
Attractoids projectiles will simply fall straight down if there is no enemy alive at the start of the round (death by Earthquake).