Electric Discharge ability of Jellyfish Necklace triggers a short electric chain that bounces between neayby targets and each bounces may trigger Starfall ability of Midnight Mantle. When there are multiple high-health targets and ability level of Electric Discharge and Starfall are high enough, a electric chain may bounce many times and summon a huge number of falling stars, which can cause serious tick loss.
I made tests with LvL.35 Electric Discharge and LvL.55 Starfall. Here are some results.

Result of electirc chain bounces between 30 iron golems

Result of electirc chain bounces between 30 wardens

Result of electirc chain bounces between 30 sheep(AI disabled) with immortality effect. Trying to save world in this case will cause the game to freeze.