My Little Pony

My Little Pony was a popular series of toys.

Santa Claus, in an attempt to convince Shona McCullough that he was real, said three words to her: "my little pony". This caused her to react defensively and hold her fingernails to his face, threatening to "mark" him. (TV: Last Christmas)

Influence
This popular toy series spawned a franchise which included comic and television adaptations which have been influenced by Doctor Who.

Television
Some background characters in the television series resemble pony versions of the Master, Third, Fifth, Eleventh, and most notably Tenth Doctors. The, originally a background character nicknamed "Doctor Whooves" by fans (based on his hourglass marking) was later called "Time Turner" in 2012, but this was later changed to "Dr. Hooves" in 2013.

A pony named has also been seen twice in the company of Dr. Hooves, the  (It Ain't Easy Being Breezies) in particular also showed Hooves wearing 3D glasses in her company, as in Doomsday, where instead of Cybermen or Daleks they send Breezies back through a dimensional rift.

The allusion is made far more explicit in the 100th episode Slice of Life, where he is called Doctor/Doc, speaks with an English accent, is fascinated by science and time travel, having studied them for "centuries", wears a bow tie and later a long, colourful scarf, and even yells "Allons-y!".

Comics
went beyond the hourglass mark and also parodied the hat, curly hair and scarf of the Fourth Doctor.

references the orange-brown scarf of the Fourth Doctor, a street lamp shaped like the TARDIS and a pony-shaped Weeping Angel.

Actors

 * John de Lancie, who played Allen Shapiro in Torchwood, voiced Discord on Friendship is Magic.

Merchandise

 * DWM 481 advertised the Dr. Hooves pony toy as a stocking stuffer.