You’re probably thinking of Nichrome, which has been the bog standard for vape coils since forever. It’s the same metal as used in most toasters, used because its resistance doesn’t change with temperature. The ‘high end’ version is Kanthal, which is even more stable at high temperatures (and it tastes better). They’re used because most heating applications need a consistent power delivery based on a constant voltage input, which you don’t get if the resistance changes as it heats up (power = volts-squared/resistance).

But then, for vaping, temperature control (TC) came along. This prevents burnt hits, and can help get the best flavour out of e-juice because some flavours are temperature-sensitive. TC relies on using a metal which does change resistance with temperature, because this is what allows the technology to measure the temperature of the wire. For safety, resistance needs to rise (not fall) as it gets hotter. Early TC used nickel, whose resistance increases a lot with temperature, but the tech is now good enough to work with stainless steels, whose resistance changes so little that it can be used in both watts mode and TC mode.

This has been your enitrely irrelevant interlude. Back to bike tyres.

I think you’re thinking of Nichrome.