Cannon Death Warp
In the Mermalair Main Chamber, Mermaid Man tasks Patrick with repairing his TV by throwing a melon at 3 buttons. Each button has its own challenge, one of which being a cannon that shoots rocks that Patrick must dodge. The cannon button is usually pressed last in speedruns.
After pressing the final button, the player can intentionally die from the cannon if their health is down to one underwear. Depending on the cannon RNG and the death animation, this can save time over walking back to Mermaid Man for the golden spatula.