Yes, thousands of volts can certainly be lethal under the right conditions. The danger posed by high voltage depends on several factors, including the current (measured in amperes), the path the electricity takes through the body, the duration of exposure, and individual health conditions.
While high voltage can cause serious injuries or fatalities, it's important to note that it's not just the voltage that matters; it's the combination of voltage and current. For instance, even relatively low voltages can be dangerous if the current passing through the body is sufficient.
Electrical safety is crucial, and it's best to avoid situations involving high voltage, as it can lead to severe injury or death. Always take precautions and respect safety standards when working with or near electrical systems.