You can Tribute 1 monster; inflict 500 damage to your opponent.
Rulings
Netrep Rulings
"Cannon Soldier's" effect is Spell Speed 1 and is an Ignition Effect.
"Cannon Soldier's" effect may be used once immediately upon summoning before the opponent may respond with an appropriate Trap Card like "Torrential Tribute" or "Trap Hole."
"Cannon Soldier" may Tribute itself for its effect.
DARK|
Level 4|[ Machine / Effect ]
ATK 1400|
DEF 1300