Bring a medium pot of water to a boil.

Add shrimp and cook for 1 minute 30 seconds.

Drain and shock in a large bowl of ice water.

Drain and set aside.

Combine sliced yellow onion, garlic, cider vinegar, lemon juice, olive oil, fennel seeds, coriander seeds, and bay leaf in a nonreactive bowl, Mason jar, or other container.

Add cooked shrimp and stir well.

Place in fridge for at least 45 minutes and up to 2 days for pickling.

Combine tomatoes, cucumber, red onion, bell pepper, and smashed garlic in a large bowl.

Sprinkle generously with salt and pepper.

Drizzle olive oil and sherry vinegar on top.

Let stand 30 minutes at room temperature to macerate.

Toss all ingredients with a wooden spoon or with your hands until evenly incorporated.

Transfer half of the contents, including liquid at bottom of bowl, to the jar of a blender.

Blend on high speed until completely smooth, about 3 minutes.

Press mixture through a fine-mesh strainer into a large bowl.

Repeat with remaining mixture (you may need to work in more batches).

Season with more salt, pepper, and vinegar as desired.

Pass through strainer one more time.

Pour mixture into a large pitcher.

Add gin, horseradish, lemon juice, Worcestershire sauce, and hot sauce.

Adjust to taste.

Set out 6 tall beer or Collins glasses.

Fill with ice and pour drink on top.

Garnish each rim with 3 pickled shrimp.