These metals melt when pushed together

TL;DR

Gallium and indium form a liquid metal alloy at room temperature when combined, and adding tin creates galinstan, stable down to -19°C.

Key Points

• 1.Gallium and indium spontaneously form a liquid alloy when pressed together. The two metals mix to create an alloy that is liquid at room temperature, causing the indium piece to visibly fall apart and produce liquid metal within minutes.
• 2.Adding tin creates galinstan, a superior mercury-like alloy. With tin included, the resulting alloy stays liquid down to -19°C (-2°F) rather than just around room temperature, making it far more comparable to mercury in behavior.
• 3.Dilute acid and cotton filtration purify the alloy into shiny liquid metal. After melting with a heat gun, acid separated the metal from the glass, and squishing it through cotton produced a clean, mirror-like liquid nearly indistinguishable from mercury.