Name the Odd One Out!

[Red Knight]

Normalize is the only one here not introduced in Gen 6 and the only one to not be possessed by a Mega Evolution. It was also the only one that did not boost moves of the type it transformed moves into prior to Generation 7.

Aerilate is the only one here exclusive to Mega Evolutions.

Fire Blast
Thunder
Blizzard
Hurricane
Hydro Pump
Focus Blast

 

[c la fet]

Hydro Pump doesn't have an additional effect


Pikachu
Hariyama
Koraidon
Elekid

 

[Red Knight]

Koraidon is the only dual-type, the only single stage, and the only Legendary.

Elekid is the only one who has never had a signature move. The Pikachu line has Volt Tackle (and the Partner Pikachu moves), Hariyama had Smelling Salts, and Koraidon has Collision Course.

Hydro Pump doesn't have an additional effect

I also would have accepted Focus Blast, because it is the only one that does not benefit from weather in some way (Fire Blast and Hydro Pump get power boosts and the other three get perfect accuracy).

Soft-Boiled
Feint Attack
Bubble Beam
Ice Beam
Conversion 2
High Jump Kick