Mammals

The biggest land animal is the African Bush Elephant.

They can weigh up to 6,000 kg (13,000 lb) and stand up to 3.3 m (10 ft 10 in) tall at the shoulder.
Source

The answer depends on the context! Here are a few possibilities:

• A mouse? I heard a mouse! (referring to the animal)
• A mouse? I need a mouse for my computer. (referring to the computer peripheral)
• A mouse? That guy is a real mouse! (referring to someone timid)

The animal with brown spots and a blue tongue is the Giraffe.

Giraffa camelopardalis, the giraffe, is an African artiodactyl mammal, the tallest living terrestrial animal and the largest ruminant. It is traditionally considered to be one species, with nine subspecies. However, research in 2016 proposed classifying it as four distinct species.

Some key characteristics include:

• Height: Giraffes can grow to be 14 to 19 feet tall.
• Spots: Giraffe spots vary in shape and size depending on the subspecies.
• Tongue: Giraffes have a distinctive blue or purple tongue, which can be about 18 inches long.

You can verify this with a quick search on a reputable source like:

African Wildlife Foundation - Giraffe