From Worms Knowledge Base
A worm is the primary controllable game object in every Worms game. It exists as a part of a team and is controlled by that team's controller. Each worm inherits all the usual game object attributes, plus has several of its own variable attributes: team, state (such as standing, walking, falling, rolling, or drowning), selected weapon, aiming angle, health, whether it has God mode, and whether it is anchored. The visible sprite is determined by its state.
Each worm has an irregularly-shaped collision mask (also known as a "hit box", but we say "collision mask" due to its irregular shape) which is 9 pixels wide at its widest and 16 pixels tall at its tallest. This collision mask always has the same size and shape, regardless of the worm's state.