Thank you Random_Fandom for making this gif.
Stashed in: Children, gifs, Best Videos, Reaction GIFs!, High Quality gifs, matt01ss, Ice Cream!
Source is 6 seconds in:
matt01ss made several more high quality gifs from that video:
How I Met Your Mother Marshall and Lily Miracle gif
Summer Glau Smile gif
Taco Mouth gif
Disney Treasure Planet gif