Sea Stealth Attack

Sea Stealth Attack — Power Evaluation

Final Score: 56 ± 6 · Confidence: Medium

• Intrinsic: 55.2 · Deck: 57.3 · Meta: provisional
• Primary role: Floodgate/Control · Secondary: Removal, Utility

Why it scores here

Sea Stealth Attack is a Umi-locked control trap whose value comes entirely from enabling and protecting the 'Umi' floodgate: on activation it can activate an Umi from hand or GY, and while Umi is on the field it prevents destruction of your face-up Spells/Traps and grants recurring battle-phase destruction against any monster that battles a Level 5 or higher WATER monster. It is a genuine 1-2 copy staple in the Umi Control shell (avg 1.68 copies, 145 Umi decks, top partners Fish Sonar and Kairyu-Shin), so its deck fit is real, but it builds no board and provides no combo conversion. Its 0 ATK/DEF and Trap typing earn nothing here — the score reflects conditional, Umi-dependent disruption, not stats.

Axis scores

Calculation

Weight profile: 0.7 Floodgate/Control + 0.3 Removal. Intrinsic ≈ 55.2, Deck ≈ 57.3, Meta = provisional. Modifiers: none. Final formula: 0.40*Intrinsic + 0.60*Deck

Strengths

• On activation can activate an 'Umi' from hand or GY, giving the deck reliable access to its key field-spell floodgate.
• While Umi is on the field, protects face-up Spells/Traps from destruction by opponent's card effects, and that protection persists even if this card leaves the field.
• Provides recurring battle-phase removal: destroys any opponent's monster that battles your Level 5 or higher WATER monster.
• Compact 1-2 copy staple with no garnet cost and no self-locking restriction.

Weaknesses

• All effects after activation are contingent on 'Umi' being on the field.
• Being a Trap, it is slow (must be set and waits a turn) and is not reachable via the deck's common WATER-monster searchers.
• Offers no combo or board-building value and provides no body.
• The destruction effect is conditional on a Level 5 or higher WATER monster actually battling an opponent's monster.

Counters / choke points

• Effect negation/counter traps (e.g. Solemn Judgment) on activation or on the gained effects.
• Cosmic Cyclone / Twin Twisters and other banish or non-destruction removal that bypasses the protection clause.
• Removing or negating 'Umi' so the card loses both of its granted effects.
• Effects that prevent battle or end the Battle Phase before the Damage Step.

Best use

Control-support trap — protect Umi/backrow and remove threats in battle. Decks: Umi Control, Umi, Phantasm Spiral. Suggested copies: 2.

Evidence & gaps

• Verified: Card text: on activation you can activate 1 'Umi' from hand or GY.; Card text: while 'Umi' is on the field this card grants protection of face-up Spells/Traps from destruction by opponent's card effects, even if this card leaves the field.; Card text: at the start of the Damage Step, if your Level 5+ WATER monster battles an opponent's monster, destroy that opponent's monster.; It is a Continuous Trap with 0 ATK/DEF and belongs to the Umi archetype.
• Observed: Ran in 400 sampled decks, all in the main deck, average 1.68 copies (max 3).; Inclusion concentrated in Umi (145 decks, 36.2%) and Umi Control (28, 7%), with Phantasm Spiral and Shark at 34 each (8.5%).; Top partners: Fish Sonar 78%, Sea Stealth II 69%, Kairyu-Shin 68.5%.; One guide (Umi Control) lists it in its CORE section.
• Inferred: Trap access is slower and less searchable than the deck's WATER-monster searchers, so it is drawn rather than tutored.; Its whole effect suite is dead without 'Umi' on the field, making its value contingent on the floodgate staying up.; The banish cost returning in the End Phase makes the protection effect roughly cost-neutral.
• Data gaps: no combos supplied — combo conversion is text-only inference no banlist token — assumed 3 copies (unlimited) no usage statistics (StatisticsCard) — archetype inclusion % inferred from deck sample only no average power index or starter-count data to measure board impact