Which game introduced the character Crunch Bandicoot?

Crunch Bandicoot was introduced in Crash Bandicoot: The Wrath of Cortex.

Released in 2001, The Wrath of Cortex is the fourth main Crash Bandicoot game and was developed by Traveller's Tales. Its story introduces Crunch as a genetically enhanced superweapon created by Dr. Neo Cortex to destroy Crash Bandicoot.

Cortex powers Crunch with the Elementals, a group of magical masks representing earth, water, fire and air. Crash and Coco must collect crystals to put the Elementals back into hibernation before facing Crunch at full strength. After Crash defeats him, Crunch breaks free from Cortex's control and becomes an ally rather than remaining a permanent villain.

The character is sometimes confused with later Crash additions from Crash of the Titans or Crash Twinsanity. Those games feature different storylines and character introductions. Crash Bandicoot 2: Cortex Strikes Back predates Crunch and focuses on Cortex's plan to use Crash to collect crystals.