Thunder Syphon (サンダーアスピル, Sandā Asupiru?, lit. "Thunder Asper") is an ability in Kingdom Hearts III. It allows the user to recover their MP when Thunder damage is taken. The greater the damage taken, the greater the MP recovery.
In Kingdom Hearts III, Thunder Syphon is a support ability. It can be multi-installed to increase its effect.
Learning Thunder Syphon
Kingdom Hearts III