When Teemo, Strategist is revealed from hidden against Deadbloom Predator, must you activate Teemo's effect and pay the Deflect cost?

Ruling: Yes, you must activate Teemo, Strategist's effect when revealed and must pay Deadbloom Predator's Deflect cost because the effect is mandatory and requires targeting an enemy unit.

Sequence:

• Teemo, Strategist is revealed from hidden (no cost for revealing)
• Teemo's mandatory effect triggers
• You must select an enemy unit as a target
• You must pay that unit's Deflect cost (1 rune for Deadbloom Predator)

Nuances:

• You do not pay any cost for revealing a unit from hidden; the power cost was already paid when initially playing it as hidden
• The total cost is only 1 rune (for Deflect), not 2 runes