Pretty pictures

No radiation, but it is diatomic
This is a scanning electron micrograph of a diatom, a single-celled organism and a type of phyoplankton. Diatoms are known for the varied appearance, specifically that of their silica-based outer walls, also known as frustules. This diatom isn't naturally red - that's just the false color - but it does naturally have that radiation-warning pattern.
The image is from Anne Weston of the  London Research Institute of Cancer Research UK and is a 2012 Wellcome Image Award winner.