Mr. Blizzard

Mr. Blizzards are living snowmen that jump up and down and can throw snowballs.

Super Mario 64
In Super Mario 64 (And Super Mario 64 DS), they are found in the Cool, Cool Mountain stage and can be defeated by running around them, just like Mr. I's can be defeated. In the remake, Wario can kill them in one punch.

In Super Mario 64 DS, their look changed. They have a zigzag mouth, wear a blue bucket and have a yellow mitten instead of pink one, but aside from this, their attack pattern remains the same. Their faces resemble to Freezies' faces.

Mario Pinball Land
In Mario Pinball Land, they appeared as residents of Frosty Frontier.

Dance Dance Revolution: Mario Mix
In Dance Dance Revolution: Mario Mix, Mr. Blizzards could be found in Freeze Mountain.

Mario Kart series
In the Mario Kart series, they usually appear as obstacles but they are often replaced with generic Snowmen.

Mario Party series
Mr. Blizzards also appear as items in the Mario Party series in Mario Party 5, Mario Party 6, and Mario Party 7. In each game, if their space is triggered, the player who triggered it will lose all of their items. A Mr. Blizzard was also a partner in Battle Mode in Mario Party 3.

Trivia

 * It is possible that they're related to the Dr. Freezegoods of Super Mario World 2: Yoshi's Island. Also, a Super Mario 64 character known as Headless Snowman resembles them.