I first discovered this trick while playing in the Asgard simulator (though it will work any where), and, thus far, only works with Colossus. When confronted by a foe without,/i> a usable weapon and one with a usable weapon, take hold of the unarmed foe using BLUE button attacks and while still holding your prey, grab the weapon from the armed foe by pressing BLUE followed by rapidly pressing GREEN.

The enemy who was in your grasp will now be stuck from head to waist in the ground, with their feet kicking in the air (and immune to further interaction). The weapon you now hold cannot be destroyed unless it is stolen from you or you drop it. This really came in handy when trying to max out my outfits and levels in the Asgard simulator. The Loki Troll mace destroys hordes of foes in just one or two swings.