You must either bounce, banish, tribute, take control of or destroy Colossal Fighter with an effect to get around him.
Destroying him by battle is usually a complete waste of time.
COLOSSAL FIGHTER:
1 Tuner + 1 or more non-Tuner monsters
This card gains 100 ATK for every Warrior-Type monster in any Graveyard. When this card is destroyed by battle and sent to the Graveyard:
You can target 1 Warrior-Type monster from either player's Graveyard; Special Summon that target.