蠱 combines 蟲 (insects) over 皿 (dish), suggesting worms or insects breeding in a container, which came to represent corruption and bewitchment.
Meaning mnemonic
A dish 皿 full of writhing insects 蟲: imagine opening a rice container and finding it infested with worms, a hidden corruption that leads you astray from what you expected.
Reading mnemonic
For コ, picture a container of rice that has gone bad: the core of the container is rotten, and 'core' cues コ while the worms spoil the dish.
