Fantastic Beasts: 28 Easter Eggs & References You Must See

The Erumpent that Newt and Kowalski are forced to track down and capture in the zoo (using the medium of sex dancing) has previous with the Harry Potter films. An Erumpent horn is housed in Xenophilius Lovegood's home (though he claims it belongs to a Crumple-Horned Snorkack) and it's the instrument that Harry, Ron and Hermione effectively use to escape when the notoriously volatile material blows up.

It looks nothing like what the Erumpet looks like in Fantastic Beasts, but it's nice that the whole "volatile horn" thing is used again for the gag that the creature is both volatile and horny.

In another link to the Lovegood family, Newt Scamander's grandson Rolf will go on to marry Luna Lovegood in the future, which is fairly ironic given how tenuous Luna's knowledge of fantastic beasts actually is.