It launches a pillar of fire that holds the opponent aloft. Beat on your incapacitated opponent, by all means.
Entei is a Fire-type Legendary Pokémon introduced in Generation II, and is categorized within the Pokédex at #244 as the "Volcano Pokémon". Along with Raikou and Suicune, Entei is part of a trio commonly referred as the legendary beasts: in Pokémon Gold and Silver and their remakes Pokémon HeartGold and SoulSilver they can be found in the Burned Tower, however when interacted with they run away. Entei can then be found randomly in any route, and will attempt to run away whenever it gets a free turn unless it gets trapped by a move like Mean Look or an ability like Shadow Tag: however, any damage and status conditions received will be retained.
Fire Spin is a Fire-type move that Entei can learn naturally. While weak (35 base power, 15 before Generation V) it traps the opponent for five turns, inflicting damage at the end of every turn and preventing it from fleeing or being switched out.