Sak Yant or Yantra Tattooing are believed to give the wearer magic powers associated with healing, luck, strength, and protection against evil.
You can get these here in thailand by a monk, they look beautiful but I’d never recommend it. Essentially, you’re making a pact with a spirit to protect you in exchange for sacrificing an activity or habit you may have previously enjoyed (the monk decides what this is, not you). These tattoos are contracts.
Breaking your side of the bargain may encourage the spirit to ‘punish’ you, and these contracts are not easily voided.