by 
Watch the tutorial
Step 1: Apply Spherize to your clip
Open the Effects panel (Window > Effects) and type Spherize into the search box. You will find it under Video Effects > Distort. Drag Spherize onto your video clip in the timeline.
Faster with BetterFX: skip the Effects panel. Press your BetterFX shortcut, type the first letters of Spherize and press Enter to apply it to the selected clip. Get BetterFX
Step 2: Add the first keyframes
Keep the clip selected and open Effect Controls. Scroll down to Spherize and click the stopwatch icon next to Radius and Center of Sphere to turn on keyframes. With the playhead at the start, set Radius to 0 so the effect starts out invisible.
Step 3: Grow the radius
Now move the blue playhead forward a bit and increase the Radius value. Keep going until the sphere is bigger than the person's head, so the whole head sits inside the bulge. Premiere Pro creates the second keyframe automatically as you change the value.
Step 4: Move the sphere onto the head
Next, change the Center of Sphere value so the effect is located on the person's head. Use the position values in Effect Controls and watch the Program Monitor until the head is in the middle of the bulge. If the person moves during the clip, add more Center of Sphere keyframes to follow them.
Step 5: Make the effect pop with Hold keyframes
To remove the smooth animation so the head snaps big instead of slowly inflating, select the Radius and Center of Sphere keyframes. Then right click one of them, choose Temporal Interpolation and select Hold. The values now jump from one keyframe to the next, which gives the effect a sudden, meme style punch.
That is it. Play the clip back and your big brain effect is done.
Tips
- Want it smoother? Skip the Hold step and use a real easing curve instead, so the head swells in gradually.
- Use a high radius carefully. A bulge that is too big pulls in the background and can look messy, so stop when the head is just covered.
- Pair it with a sound effect. A short pop or boing at the moment of the jump sells the joke.
FAQ
Where is the Spherize effect in Premiere Pro?
Search for Spherize in the Effects panel. It sits under Video Effects > Distort.
How do I make the effect appear suddenly?
Select the keyframes, right click, choose Temporal Interpolation and pick Hold. The effect then jumps between values without any in between animation.
How do I keep the effect on a moving head?
Add extra keyframes to Center of Sphere and move the position along with the head.
Animating effects like this gets much easier with EaseFlow, which applies smooth easing curves to your keyframes in one click.
