Toxic

Toxic (どくどく Excessive Poison) is -type status move introduced in Generation I. It has been TM06 since Generation I.

Description
A move that leaves the target badly poisoned.

In battle
Its poison damage worsens every turn.

Contests
Worsens the condition of those that made appeals.

Super Contests
Prevents the Voltage from going down in the same turn.

Contest Spectaculars
Brings down the energy of any Pokémon that have already used a move this turn.

By TM
All Pokémon that can learn TMs can learn Toxic by TM06 except the following:

Trivia

 * This is the most learned TM in the main series games.