The MF Like Button

The MF Like Button is a red button with a "thumbs-up emoji" on it, and 2 yellow "okay" symbol emoji on the upper sides in a placement resembling a sort of decorative pair of wings.

The MF Like button is an expression of love, and as such, is powered by positive feelings, especially clicking "like" on rips that you love. However, the love-powered ability that the button has is never explained.

Appearances
The MF Like Button first appeared in the Reboot finale, "Melody of the Heart ~True Ending~". After The Voice tries to convince Chad Warden to rule the channel by his side, Chad gives a speech about how SiIvaGunner owes nobody nothing and they're just doing what they love because they love it. Chad then pulls out the button and sacrifices himself to kill The Voice, but it is not certain if the button itself caused his death and the recoil of its power killed Chad, or if some other force did.

Some time in August 2016 (or very late July), the MF Like Button was added to the /r/GiIvaSunner subreddit, replacing the upvote. The downvote was also replaced with an image of a "Dislike Bomb", although this item has never appeared on the channel.

A little over 3 years later, the MF Like Button reappeared in the King for Another Day Tournament fake finale, "The FINAL BOSS approaches...", with John Notwoodman telling the viewers to "like" the video to boost the power of the MF Like Button so it can defeat The Crown and Unrestrained HyperCam 2. In "THIS GAME'S WINNER IS... [FINAL BOSS BATTLE]", we can see that this plan was successful. We also see a thumb-giving hand "punch" the crown off of HyperCam's icon, but it's not clear if this is meant to be literal.

Trivia

 * In its original Reboot appearance, it is referred to exclusively in all-caps, but in its King for Another Day appearance, it's sometimes referred to with normal capitalization.
 * A variant of the button ("MF SELF DESTRUCT BUTTON") appears in "Ending - Phineas and Ferb: Day of Doofenshmirtz".
 * Another variant ("MF On Button") appears ""There will never be a Touhou Album announcement."".