Penetration is a Braverydeck specific effect card. When used on an enemy monster with Taunt, the monster gets silenced. If used on an enemy monster without Taunt, you will draw a card instead.
Both effects are particularly useful for Bravery. Removing Taunts helps get rid of opposition to Bravery's assault on the enemy player, and drawing cards always helps you to keep playing more useful monsters at the cost of running out of cards faster.
Keep in mind that Silencing will also remove effects like Can't attack from monsters like MTT Fountain or Dog House.