Tidal Whale (also known as Tidal Makkoeen in Japan and Duff McWhalen in the original American release) is a whale-based Reploid and a boss in Mega Man X5. A former captain of a maritime security force, his reckless behaviour often caused tension between him and Repliforce's naval division. He later became the curator of an oceanographic museum, but turned Maverick when the Sigma Virus was scattered worldwide. When the Maverick Hunters attempted to acquire a stockpile of hydrogen from the ocean to power the Enigma Cannon, Whale stood in the way, challenging them to a battle to the death.
- Ice Block - Whale releases blocks of ice from his mouth to push his foes back. These blocks can be used as platforms.
- Goo Shaver - A blob of cryogenic goo launched from Whale's blowhole that creeps across surfaces. X can copy this weapon and Zero's Flying Splasher technique is based on this attack.
- Tidal Torpedo - Projectiles that home in on targets. These torpedoes can be destroyed.
Whale's thick chassis can be quickly cleaved through with high-frequency vibration attacks, making him vulnerable to the Crescent Shot and Crescent Slash.