As you can see, Star Catcher is taking part in the Fusion Summon process. Here's the card's info:
Pony Fusion
Normal Spell
This card's name is treated as "Ponymerization". Discard 1 card, then remove from play Fusion Material Monsters listed in a "My Little Pony Fusion Monster Card from your hand, field or Graveyard and Special Summon that Fusion Monster from your Extra Deck. (This Special Summon is treated as a Fusion Summon.)
Rainbow Rare