vine
薁 refers to a type of vine, specifically a plant that grows in a creeping or climbing manner.
薁 is a phono-semantic compound: the grass radical 艹 indicates a plant, while 奧 likely contributes the sound. The exact historical development is uncertain.
The top 艹 shows it's a plant, and the bottom 奧 looks like a tangled, deep interior. Picture a vine growing deep into a thicket, its stems twisting through the dense undergrowth.
For イク, imagine the vine growing thick and quick: "eek, you!" — the vine surprises you with its speed. "Eek" cues イク.