You've mastered using your Tortle shell in combat and have the following benefits:

• Increase your Strength or Wisdom score by 1, to a maximum of 20.
• Your base AC becomes 18, instead of 17.
• Shell Slam. As a reaction to an enemy ending its turn within 5ft of you, you may attempt to push it 5ft away or knock it prone with a Shove from your shell. You are proficient with this Strength (Athletics) ability check. The target must be no more than one size larger than you.