Final answer:
The phrase refers to expressing one's opinion passionately, but the association with marriage and animal transformation seems metaphorical. Without additional context, it's unclear which specific animal is referred to or if this is part of a cultural expression or literary reference.
Step-by-step explanation:
The phrase "soap box moment" typically refers to a situation where an individual expresses their opinions passionately or takes a stand on a particular issue. However, the reference to marriage and individuals becoming an animal seems to be a metaphor or an idiomatic expression rather than a literal transformation. Unfortunately, without further context, it's challenging to provide a specific answer to what animal they become. The question possibly pertains to a piece of literature or a cultural saying where, upon marriage, individuals might be humorously said to become a certain animal representing traits or behaviors expected in marriage. For instance, in some contexts, a person might say that individuals become "old ball and chain," suggesting they are no longer as free as they once were, but this is by no means universal and can be considered a dated and derogatory commentary on marriage.