Cruel mode

Cruel Melee is a mode found in Super Smash Bros. Melee under the Multi-Man Melee section. The mode is unarguably the most challenging, as the opponents will be immensely challenging compared to the enemies of the other Multi-Man Melee modes.

The amount of enemies each character kills can be found on Cruel Melee's character select screen.

Rewards
If you are capable of killing five or more of the Cruel Melee enemies with a single character, then you'd come in possession of the Mr. Resetti trophy.