They are the only enemies (aside from Doctor Purnell) who attack Simon with a firearm instead of melee weapons, charging towards him with a Glock 19, firing rapidly and inaccurately with no care for self-preservation.
Tips
Suiciders are perfect means for acquiring large amounts of Glock ammo since they drop their guns when killed.
Once the Suicider has emptied its magazine or the player has gotten too close, it will stop and raise the Glock to its own head, killing itself.
The player can either choose to face the creature in a gun battle in which headshots are extremely effective and easy to pull off due to its big head or just getting near to it so that it will automatically shoot his head to suicide.
If the player does not have a Glock in his inventory and picks one up from a Suicider that has killed itself, there will still be a bullet in the chamber, though it will still provide a full magazine if the player has a Glock.
Be careful on Nightmare mode as they can get headshots which will result in an instant kill as it does 180 damage.
In the co-op campaign Manhunt, they wield a Ruger P345 instead of the Glock.
Relevance to Simon
The Suicider represents Simon's desire to end his own life, as getting close to the suicider or if it has no ammo left will result in it shooting itself in the head.
Trivia
Like Slower 1, the Suicider has a head texture that says "E.T."
