Capture every opponent's head square. The last player with a living head wins.
Each turn you take exactly one action — place a piece or bite.
Place the current piece shown in your hand. The piece must be placed orthogonally adjacent to territory you already own and cannot overlap any occupied cell. Use R to rotate before placing.Use the rotate button to change orientation, drag to position, then tap Place.
Press B (or the Bite button), click a starting cell adjacent to your territory, then drag or click in a direction.Tap the Bite button, tap a starting cell adjacent to your territory, then drag in a direction. A bite removes all enemy cells in a straight line extending from your chosen starting cell. The starting cell can be empty — you can bite across a gap to hit enemies on the other side. Bites cannot be used to kill an enemy head — any head cells along the line are skipped. Cells cut off from their head vanish automatically after the bite.
Bite length grows with your colony. The larger your territory, the farther each bite reaches (length = 1 + your cell count ÷ a configurable divisor, default 30). Your current bite length is shown next to your bite gems in the sidebar. Each player has a limited number of bites.
The four corner squares each hold a bonus bite (). Grow your fungus onto a corner to collect it and add one bite to your supply.
After you place, any run of enemy cells flanked on both ends by your cells — in a row, column, or diagonal — is captured and becomes yours. Board edges don't count as walls.
Every cell must stay connected to its owner's head square through a chain of that player's cells. Any cells cut off from the head are removed from the board immediately after each move.
When a player's head square is captured, they are eliminated. By default their remaining cells are cleared from the board. If the host enables Inherit on capture, the capturing player instead takes control of the entire eliminated fungus.
You may pass at any time. If all living players pass consecutively, the game ends immediately and the player with the most cells wins. You are auto-skipped if you have no legal placements and no bites remaining.
Click Resign at any time to forfeit. All your cells are immediately cleared from the board and you are eliminated. Click twice to confirm.
| Arrows / WASD | Move piece |
| R / Space | Rotate piece |
| Scroll wheel | Rotate piece |
| Click / Enter | Place piece / bite cell |
| B / Middle-click | Toggle bite mode |
| Esc | Cancel bite mode |
| Drag | Reposition piece |
| Double-tap | Rotate piece |
| Rotate button | Rotate piece |
| Bite button | Toggle bite mode |
| Place button | Confirm placement |
InternetFungus is based on NetFungus by Andrew Schaaf, itself inspired by Fungus by Ryan Koopmans.