DuckTales (1987)

S3E16 Attack of the Fifty-Foot Webby

Feeling neglected, Webby unexpectedly transforms into a giantess after tumbling into an enigmatic jungle pool. Although she finds herself the focus of everyone's attention, it’s not the experience she hoped for. Meanwhile, Scrooge is on a quest to find a solution to shrink her back to size, but their troubles escalate when a shady circus owner plots to abduct Webby for his latest attraction.