Reserving for bidoof rocks. Will edit in ASAP.
EDIT: bidoof rocks, take Eggless the Chansey. Chansey, as you know, are known for their delicious eggs, as well as their caring nature. However, the one you caught has a genetic defect that blocked the production of her ovaries, meaning that she can never lay eggs, thus she can never learn/know an egg-related move (Egg Bomb, Softboiled, etc.). She must also hold an Oval Stone at all times, and if it is taken from her by any means, she must switch out immediately for the duration of the battle. Eggless, due to her unfortunate disability, was shunned by her colleagues, so she must Solo every Chansey you fight. Because she was forbidden from breeding with other Pokemon, she is quite agressive, and must know at least 2 attacking moves, one of which must be Normal-Type. To evolve, Solo 5 wild Chansey, so she can finally put the incident behind her.
EDIT: bidoof rocks, take Eggless the Chansey. Chansey, as you know, are known for their delicious eggs, as well as their caring nature. However, the one you caught has a genetic defect that blocked the production of her ovaries, meaning that she can never lay eggs, thus she can never learn/know an egg-related move (Egg Bomb, Softboiled, etc.). She must also hold an Oval Stone at all times, and if it is taken from her by any means, she must switch out immediately for the duration of the battle. Eggless, due to her unfortunate disability, was shunned by her colleagues, so she must Solo every Chansey you fight. Because she was forbidden from breeding with other Pokemon, she is quite agressive, and must know at least 2 attacking moves, one of which must be Normal-Type. To evolve, Solo 5 wild Chansey, so she can finally put the incident behind her.