Expanded Sentries/Wrangler

The Wrangler is a pre-hardmode tool. It is sold by the Mechanic. While being channeled, all Expanded Sentries turrets in range will fire at your cursor, overriding their NPC targeting. Its color changes to reflect your team color in multiplayer.

Trivia

 * This tool is based off of the Wrangler from Team Fortress 2.