You met Fluk!

You raise some pseudopods towards a creature in range. You touch a creature, and that creature must succeed on a DC14 Wisdom saving throw or Stackable is triggered.

Stackable. If the creature already cursed by the Fluk's acquaintance, it does not incur another curse, but the previous curse's counter increases by one. If the creature doesn't cursed with Fluk's acquaintance, become cursed with it and set the counter to 1.

Fluk's acquaintance. When a Fluk hits you and you takes damage from that attack, take additional bludgeoning damage equals to the curse's counter. Various reduces, resistances and immunities can be applied to this damage.