Mark of the Hydra

You have manifested the mark of the Hydra. Determine its appearance and choose one flaw associated with it. You gain the following benefits:

• You regenerate 4 hit points at the start of your turn but cannot gain hit points above your hit point maximum from this feat. You do not regenerate hit points if you have taken acid or fire damage before the start of your next turn.
• You can hold your breath for 30 minutes.
• You do not need to sleep.  Instead, you must rest for 4 hours to gain the benefits of a long rest. 

Choose one flaw:

• You are vulnerable to fire damage.
• You are vulnerable to acid damage.