Cobalt is an element obtained from the smelting of metallic ores such as cobaltite, copper, and nickel. The smelted form is a hard silvery metal with magnetic properties.
Cobalt-based blue pigments have been used since the Bronze Age (3000 BC) for glass, ceramics, jewellery, and paint. In modern times, the element is also used as part of a superalloy metal (which is a combination of metals) for diverse items like prosthetics, batteries, jet engines and turbines. A radioactive isotope of cobalt is commonly used in medical tests and to sterilize food and equipment.
Cobalt Blue is the name of a deep blue pigment used in ceramics, paint, glass, and even ophthalmology filters. It’s made from cobalt salts of alumina, and its popularity is in part due to its stability (meaning it doesn’t degrade or break down quickly). However, it’s toxic if ingested, much as I’d imagine Malcolm Thawne to be.
Cobalt Blue Tarantula
The Cobalt Blue tarantula is a spider species native to Myanmar and Thailand, notable for its iridescent blue legs, speed, and aggression. Somehow…this seems fitting. This site describes them as “a psychotic, high-strung burrowing species”, which makes them seem even less appealing.
There are many similarities between a blue tarantula and Malcolm Thawne: one is despised by most people and looks ridiculous. The other is a spider.