Bloodlink

You puncture your hands with a needle and touch two creatures with your blood. Both creatures have to make a constitution saving throw against your spell DC. 

If both fail, you establish a Bloodlink between them. A dark red chain appears between them that has the following properties:

• The creatures cannot move more than 20ft away from each other.
• Whenever one of the creatures suffers damage, the other creature also takes that damage.
• The chain has 20 hp and can be destroyed with normal attacks.

If one fails and one succeeds, the chain has the following properties:

• The creatures cannot move more than 20ft away from each other.
• Whenever one of the creatures suffers damage, the other creature also takes half of that damage (rounded down).
• The chain has 5 hp and can be destroyed with normal attacks.

If both succeed, the spell fails.