an amphibious beast resembling a tiger with one horn, place name
虒 refers to a mythical amphibious beast resembling a tiger with a single horn. It also appears as a place name, likely derived from the creature or its imagery.
虒 is a rare character of uncertain origin. It visually contains 虎 (tiger), suggesting a tiger-like beast, but the exact historical development is unclear.
The character looks like a tiger (虎) with an extra horn-like stroke on top. Imagine a fierce amphibious tiger with a single horn emerging from the water.
For シ, picture the beast sheathed in water, only its horn visible: she -> シ, like the first sound of 'sheathed'.