You can grab a cobra by the neck by really slowly pushing it's head down to the ground. Start high with your hand and remember: no sudden moves.

Not op, but I always thought this was fun. For any continuous quantity, (eg temperature, humidity, barometric pressure), there's always two points on opposite ends (antipodal points) of earth with the exact same value. Its useless because there's no way to know where these points are, it assumes a perfect sphere, and apparently these quanities aren't exactly always continuous. Its the Borsuk-Ulam theorem from topology and extends to higher dimensions. It can be proven pretty easily on a circle with basic calculus.