Complex sentence: Roo's best new pal, Lumpy, is excited to trick-or-treat for the first time--until Tigger warns them about the dreaded Gobloon who'll turn them into a Jaggedy Lantern if he catches them.
Split into simpler sentences: Roo's best new pal, Lumpy, is excited to trick-or-treat for the first time. However, Tigger warns them about the dreaded Gobloon who'll turn them into Jaggedy Lanterns if he catches them.