Mash the avocados in a mixing bowl until smooth with a few small chunks. Add lime juice, salt, and garlic powder, mixing for 2-3 minutes.

Fold in diced tomatoes, chopped onion, and chopped cilantro into the avocado mixture and mix until combined, about 1-2 minutes.

Transfer the guacamole to a serving platter and create a slight indent in the center.

Scatter crushed blue corn tortilla chips over the guacamole, pressing down gently.

Arrange sliced black olives atop the guacamole to resemble creepy spiders.