Pico the Woolly Mammoth

(Woolly mammoth trumpet sound) -Pico, Sonic's Hourglass

Pico is a small woolly mammoth baby who Sonic and Sonja found in Green Hill Past during the events of Sonic's Hourglass. He was orphaned from his birth parents at a young age due to an unknown cause. While originally only attached to Sonja, he eventually warmed up to Sonic after he saved him from the bereaved mole person in the Carnage Caves under Twisted Willows. Despite the trauma he's gone through, and the predicament the events of the book place him and his new family in, he remains cheery, playful, curious, and adorable.

Personality
Pico doesn't have much in terms of personality in Sonic's Hourglass. He shows heightened and vibrant levels of basic emotions. Such as fear when he and the people he love are being pursued by a monster. At the beginning, he is very irritable and often scared, going as far as to try to attack Sonic when approached, thinking he is a predator that may eat him.

Pico is shown to have undergone early childhood trauma, likely due to being alone in the wild after the untimely deaths of his birth parents. Because of this, he developed differently than a normal child. He is very cautious and fearful of things, even if he often shows joy.

Pico retains many of his animalistic tendencies even after his rapid evolution due to time travel. This is likely due to either his different learning skills, and/or the sudden change in his body not applying to his mind. For example, while Sonic learned to not just eat berries and other plants, but instead chili dogs, because of natural evolution of his species across many years, Pico is the only woolly mammoth and was taken from his time, and evolved unnaturally due to time travel.

Pico grows each day, and has an ongoing character arc that will follow through into the next book he appears in.

Abilities
Pico is implied to have special abilities similar to Sonic's speed or Knuckles' strength early on in Part 2 as shown when he doesn't get sucked up into the Storm, whose vacuum only applies to those without some kind of special ability. This doesn't come into play until later on, when he is outright shown to possess the power to release ultrasonic sounds. These are powerful enough to blow away the corpses hanging from the ceiling in Genocide City, as well as shatter all the mirrors in the hall of mirrors within Orglace Mansion. The latter saves Team Sonic from certain doom.

This ability is amplified when Pico transforms into a Primordial being in the true finale of Sonic's Hourglass.

Pico can also Multi-Boost like Sonic and Sonja.

Trivia

 * Pico's namesake is the Sega Pico, an educational console made by Sega in 1993 to teach young children basic skills.
 * Pico was originally going to be named Tammy. The name made it far into the writing process until being scrapped in favor of Pico.