The Penguin is a weapon present in the multiplayer mode of Half-Life: Opposing Force, Capture the Flag.
The Penguin is used as a biological weapon, it can be found in nests that have the appearance of a snowman holding a sign that reads "Beware the Penguins!"; each nest contains 3 penguins. The penguin has a grenade attached to it, and thus is much more powerful than the snark due to the devastating explosion; the penguin also travels farther when thrown.
Successive penguins are thrown slower than snarks, as each one can only be thrown every 2 seconds compared to 0.3 seconds for the snarks. Furthermore, a maximum of 9 penguins can be carried at a time compared to 15 for the snarks.
Penguins can be obtained via cheats in singleplayer mode, along with the standard snarks. However, it can only be done with the "
give weapon_penguin" command.