Pak E. Derm

Pak Elephant Derms are elephant-like creatures that first appeared in Yoshi's Story.

Yoshi's Story
In the game Yoshi's Story, these little elephants hold up stop signs and don't let Yoshi pass. To pass, Yoshi has to Ground Pound the ground, and the Pak E. Derm would fall away, letting Yoshi pass. Yoshi had to act quickly, because the Pak E. Derm would get up soon. Yoshi encounters Pak E. Derm three times throughout the first level. After that, they're absent in all the other levels. Pak E. Derm's Hint Block stated the poem that is thought of synonymously with the character: "Pak E. Derm will not let you by, unless you give something special a try."

Super Smash Bros. Melee
Pak E. Derm also appears in Super Smash Bros. Melee as a trophy and in the background of the Yoshi Story stage. According to the trophy, there is only one; also according to the trophy, he's been practicing the skill of holding the sign for years. It is unknown why he would take so long, but it could refer to him having no arms and being able to hold the sign anyways, or a joke to give him a more in-depth explanation for his trophy other than something simpler.

Super Smash Bros. Brawl
Pak E. Derm is one of the many characters to appear as a Sticker in Super Smash Bros. Brawl.

Trivia

 * Pak E. Derm's name is a play on "pachyderm", another name for an elephant.