That's quite the tangent about Jellyfish. Was this discussion not about what works as a tank class?
As for the on death effect, is that not just an empowerment token? Those have since been removed from the game. Even if they still applied, the jellyfish used to be rarely empowered, so it shouldn't be that hard to deal with. Even finding two at once is a rarity, let alone all four. Be sure you have the latest version of the game.