Riot just released more detail on the champion they had been hinting at earlier this week. As expected, he seems to be a new AP carry focused especially on skillshot techniques.
Passive: Every 12 seconds, Ziggs' next attack deals bonus magic damage. This cooldown is shortened by each use of an ability.
Bouncing Bomb (Q): Skillshot that bounces and does magic damage
Satchel Charge (W): Throws a bomb that detonates after 4 seconds, or by activating the ability again.
Explosion deals damage and knocks enemies away. Ziggs is also knocked away if near the explosion, but does not take damage.
Hexplosive Minefield (E): Scatters multiple mines that explode upon enemy impact, dealing damage and slowing.
Mega Inferno Bomb (R): Long range AoE nuke. Enemies closer to the center of the blast take increased damage.
Riot's entire write-up on Ziggs can be read here.