The Time Baby is an omnipotent infant god that leads the time police and threatens anyone who should severely break the laws of space-time with a 'tantrum.'
This gif, during which he originally says 'Surrender now or face my tantrum,' can have text added to it to create reaction gifs for mocking people being completely unreasonable or whinging about really dumb things.
For example, Saints Row fans throwing a tantrum over the characters in the reboot being 'sjw hipster soyboy cuck zoomers.'