The goblin shark is known for having the sharpest teeth.
Tiger
No. Kangaroos do not have the sharpest memory. They are not particularly intelligent; not are they very trainable.
I have the sharpest eyes in my classroom.
fin whale
Humans chase any animal that an animal can't chase.
The animal you are describing is an octopus. Octopuses have suckers on their tentacles, a beak for feeding, and fin-like structures to help with movement and camouflage.
fish
Yellow fin tuna
Sharks🐬
I believe it is the fin whale.
Blue Fin (tuna)