Scytheclaw

Mana cost: {5}
Type: Artifact — Equipment
Set: Commander Masters #615 (rare)

Living weapon (When this Equipment enters, create a 0/0 black Phyrexian Germ creature token, then attach this to it.)
Equipped creature gets +1/+1.
Whenever equipped creature deals combat damage to a player, that player loses half their life, rounded up.
Equip {3}

Scytheclaw has 6 printings, first in Commander 2015 (2015). EDHREC ranks it #7,455 among Commander cards. It appears most in Nahiri, Forged in Fury decks (1,421 on EDHREC). 3 public decks on TCG run it. It has 5 official rulings.

Legality

commander: legal
legacy: legal
vintage: legal
pauper: not legal
modern: not legal
pioneer: not legal
standard: not legal
brawl: not legal

Public decks that run Scytheclaw

Growing Threat - March of the Machine Commander, led by Brimaz, Blight of Oreskos
Sneak Attack - Zendikar Rising Commander, led by Anowon, the Ruin Thief
Swell the Host - Commander 2015, led by Ezuri, Claw of Progress

Commanders that run Scytheclaw most

Deck counts from EDHREC.

Often played with Scytheclaw

Cards that show up in the same decks on EDHREC.

Rulings

2015-11-04: Scytheclaw's triggered ability triggers and resolves after combat damage is dealt. For example, if the Germ token deals 1 combat damage to a player with 10 life, combat damage will reduce that player's life total to 9. Then Scytheclaw's ability will cause the player to lose 5 life, leaving the player at 4.
2020-08-07: If the Germ token is destroyed, the Equipment remains on the battlefield as with any other Equipment.
2020-08-07: Like other Equipment, each Equipment with living weapon has an equip cost. You can pay this cost to attach an Equipment to another creature you control. Once the Germ token is no longer equipped, it will be put into your graveyard and subsequently cease to exist, unless another effect raises its toughness above 0.
2020-08-07: If the living weapon trigger causes two Germs to be created (due to an effect such as that of Doubling Season), the Equipment becomes attached to one of them. The other will be put into your graveyard and subsequently cease to exist, unless another effect raises its toughness above 0.
2020-08-07: The Germ token enters the battlefield as a 0/0 creature and the Equipment becomes attached to it before state-based actions would cause the token to die. Abilities that trigger as the token enters the battlefield see that a 0/0 creature entered the battlefield.