Tricastle

Tricastle, known as Trio de Toride (トリオデトリデ) in Japan, is a mini-boss in Mega Man 10, found in Blade Man's stage. It is a castle made up of three sections; a large, center gate with two towers on each side. Each section has a hole where a pair of eyes can be seen peeking out, which is also the weak spot of each section. Shoot this area on all three sections to destroy Tricastle.

The gate opens and closes, releasing platforms with spiked edges while it's open. These platforms are used to to reach the other two towers. Once the gate is destroyed, it will remain open and continue to release platforms. The two towers are equipped with turrets that shoot at Mega Man. Once the eyes are destroyed, the turrets will be disabled. When all three sections are destroyed, the castle will humorously raise a white flag of surrender and slowly collapse.

The speed of the spiked platforms increases with each difficulty level.

Strategy
Using Solar Blaze is effective against the 2 taller towers as it can strike both with each shot. Rebound Striker is also effective as it can be fired diagonally without using the spiked platforms. the Water Shield works good too. Also, if you bought Bass Mode from DLC, the Bass Buster can fire straight upwards, making the battle much easier than with the other playable characters.

Trivia

 * Toride means fortress in Japanese.