Heat a gas grill to medium or heat a cast-iron grill pan over medium-high heat. Grill the pineapple, turning once, until seared on both sides, about 2-3 minutes. Cut the pineapple into 4 chunks and set aside.

In a cocktail shaker, muddle together lime juice, pineapple juice, agave, and 3 chunks of grilled pineapple. Add mezcal, tequila, and ice and shake well. Strain into a glass over ice. Garnish with a remaining grilled pineapple chunk or lime. Adapted from Saveur Magazine.