Flea can inflict Blind, Poison, Chaos, and Sleep. These attacks are accompanied by minor-to-moderate damage. When Flea is below half his maximum HP, he will begin to counterattack with a technique called “The Stare.” This inflicts heavy physical damage on all of your party members. Flea will not chain this counter twice in a row.

That said, while getting hit by The Stare is dependent on RNG (it's possible for it to never happen), it has the potential to cause a Game Over very quickly. There are a few ways to mitigate or avoid the attack, however: using Shields or Lucca's Protect and making sure to top off your HP when needed is one. Another strategy is to leave at least one party member KO'd. The counterattack will not trigger under this condition.

flea plus what lol