The Javelin Gun was the first new weapon introduced in Dead Space 2. The gun was created by Timson Tools and was designed to destroy asteroids.http://faqs.ign.com/articles/114/1143782p1.html  The gun is capable of killing any of the Necromorphs with one shot. The Javelin Gun has a titanium pike, and once it is launched it will travel at high speeds until it comes into contact with a surface. If an enemy is hit by the pike, it will remain clamped to the ground so that it can be killed by Isaac.http://deadspace.wikia.com/wiki/Javelin_Gun 

The ammunition for the Javelin Gun can be purchased in the game’s store for 400 credits for two spears, but the two spears can only be sold for 200 credits. The selling price is the lowest of all ammunitions in the game.http://deadspace.wikia.com/wiki/Javelin_Gun 

The Javelin Gun also has alternative fire mode which electrifies the titanium spike. This allows it to incinerate the target on impact. The alternative fire mode can also be used in a crowded situation as a remotely-detonated mine that will instantly spread flames around the area. Once upgraded, the alternative fire mode becomes more powerful; it will split the limbs of an Ubermorph with only two shots, one bolt and one alternative fire.http://faqs.ign.com/articles/114/1143782p1.html 

When it is completely upgraded, this weapon will use two ammunitions: one javelin for the placement shot, and another to detonate the placement shot. The Ubermorph’s armor has areas where it can deflect bolts, and the bolt can rebound, leaving the player vulnerable if the bolt is beyond the range of electrocution. When using the alternative fire mode, the player must be aware of the range of the last bolt, because if he is near the bolt while using the alternative fire, Isaac can get electrocuted and will become an easy target for his enemies.http://faqs.ign.com/articles/114/1143782p1.html