The Cookie

I slip into my rocket skates AND - being faster than light - not only lose the ants but also steal the cookie out of your hand as I overtake you

I'll sprinkle you with fairy dust that will make you sleepy and steal the cookie. :D

I'll tell you the two in your profile pic are now in a real relationship. While you are distracted checking if it's true online, I'll steal the cookie.

 Nieve:

I will colour, ColourMePurple with any other colour than purple colour.

ColourMePurple is shocked to see other colour than purple colour in the mirror that 

she immediately leaves to wash this new colour and colour herself back to purple colour and 

while leaving she angrily throws the cookie which I catch with a victory smile.

Touché XD

Man it took me days to get the BL community to forget about me. XD

I offer you a chocolate bar pretending to make up for it and while you are busy opening the wrapper, I replace the cookie with a plastic replica and slowly walk away with the real cookie. :D

I take you to an Amusement Park and while on a ride the cookie slips out of your pocket. I grab it and hide it in my clothes. You are enjoying yourself you don't notice it missing until you get home. :p