独

Left dog/animal radical — the indexing component. 独 originally referred to a solitary kind of beast — perhaps a lone wolf or solitary monkey species, depending on the source. From wild-and-alone the meaning generalised to 'alone/single.' Same radical anchors many beast chars: 狗 (dog), 猫 (cat), 狼 (wolf).

Right 虫 — a stand-in for the much more elaborate right side of traditional 獨, which had a phonetic 蜀 (sole/silkworm). The simplification reform abbreviated 蜀 down to its top portion 虫. Sound-wise this leaves the phonetic transparency a little broken, but 虫 reliably marks the visual right-side handle.