Answer:
Hard to catch, easy to hold. Can't be seen, unless it's cold.
Iron on a mammal. Mammal on your feet.
I drift forever with the current down these long canals they’ve made, Tame, yet wild, I run elusive Multitasking to your aid. Before I came, the world was darker, colder, sometimes, rougher, true. But though I might make living easy, I’m good at killing people too.
Some try to hide, some try to cheat. But time will show, we always will meet. Try as you might, to guess my name. I promise you'll know, when you I do claim.
What is it something that you always have but you always leave behind?
What did the piece of wood say when he saw the screwdriver and screws approaching?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?