Sentry

• Level 1 - Sentry Deals 1 damage to a creature attacking you at random
Upgrade 3 (Pay X {c} where X is equal to the upgrade cost to level up)
• Level 2 - Sentry Deals 3 damage to a creature attacking you at random
Upgrade 9
• Level 3 - Sentry Deals 4 damage to target creature attacking you