The Wonderous Mechanical Replacement Arm (beta version) was created by Felix Bignoodle to replace the right arm of a Aasimir Cleric named Panos. It is an upgrade to his former replacement arm using the scales of the white dragon Glazhael and some enchanted bark.

Shell of Glazhael

Thanks to the scales used in its construction, this arm grants its wearer resistance to cold damage. In addition, if the user casts Dampen Elements to reduce cold damage, it is instead completely negated and the energy from the spell is stored in the arm. Every 10 points of cold damaged negated in this way stores 1 level of spells in the arm up to 5 spell levels.

Memories of the Sacred Oak

Thanks to the sacred oaken bark used in the construction of this arm, it is inscribed with three spells from the druid spell book. These spells may be chosen by the wearer after a long rest but may only be cast via the stored spell levels in the arm. 

Sturdy Construction

Due to it's sturdy construction, the arm can be used as a reaction to block an incoming attack and therefore boost the wearer's AC by 2, however doing so will cause the arm to potentially malfunction. If the user decides to use the arm to block, they will immediately roll on the following table and then again on the start of every turn till the end of combat. 

Malfunction table: Player rolls a d10

10 or 9: Nothing happens

8 or 7: The arm shows visible damage. Subtract 1 from all future rolls on this table till the arm is repaired. 

6 or 5: Arm falls limp to your side, take -1 to all AC and dexterity checks till you can reset the arm (end of combat). 

4: Electrical short. Take 1d6 lightning damage and roll a constitution save of 12. If you fail, you are stunned for a round and cannot move or act.

3: Emergency siren. You and anyone within 5' takes 1d6 thunder damage. Anyone not already alerted to your presence now know your whereabouts. Any creatures with echolocation or other sound-based perception have advantage on you.

2: Escape protocol: The arm violently rips itself free from the user, causing 2d6 bludgeoning damage. The arm then dashes away, 30' per turn, till it is either captured (contested strength or dexterity check of 12) or till it returns to Felix Bignoodle.

1: Self destruct mode activates. In 5 turns the arm will explode, dealing 8d6 fire damage to everyone within a 10' radius and pushing everyone back 20'. This will become immediate if the arm is used again to block and another roll of 1 is rolled. Countdown can be stopped either as a free action at the end of combat or by taking a full turn to remove the arm and disable it. The arm is fully destroyed in the explosion. 

Notes: Resistance: Cold, Must have equipped for 12 hours to function properly