Activated abilities of lands your opponents control can't be activated unless they're mana abilities.
Sharkey has all activated abilities of lands your opponents control except mana abilities.
Mana of any type can be spent to activate Sharkey's abilities.

: Target land becomes a Swamp until its controller's next untap step.

Collect evidence 6: This Vehicle becomes an artifact creature until end of turn.
Whenever this Vehicle attacks, you may cast an instant or sorcery spell from among cards exiled with it. If that spell would be put into a graveyard, put it on the bottom of its owner's library instead.
Crew 2

All creatures get -2/-2 until end of turn.

Heroic — Whenever you cast a spell that targets this creature, exile the top three cards of target player's library.
, Sacrifice this creature: Counter target spell with the same name as a card exiled with this creature.

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
: Add .

, , Sacrifice this creature: Return target creature card from your graveyard to the battlefield. That creature gains haste. At the beginning of the next end step, sacrifice it.

Counter target creature or enchantment spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

: Add .

Create two 2/2 white Knight Ally creature tokens.

Haste
Whenever a creature you control with haste attacks, create a tapped Treasure token.

As long as this creature is equipped, it gets +1/+1 and has flying.

Choose two target creature cards in your graveyard. Sacrifice a creature. If you do, return the chosen cards to the battlefield tapped.

You may cast up to two instant and/or sorcery spells with total mana value 6 or less from your graveyard and/or hand without paying their mana costs. If those spells would be put into your graveyard, exile them instead. Exile Invoke Calamity.

: Add one mana of any color. Spend this mana only to cast a creature spell.

Create a token that's a copy of target creature you control.
Flashback (You may cast this card from your graveyard for its flashback cost. Then exile it.)

, , Sacrifice this creature: Destroy target artifact.

Metalcraft — : Tap target artifact, creature, or land. Activate only if you control three or more artifacts.

When this Equipment enters, attach it to target creature you control.
Equipped creature gets +1/+1 and has flying and ward . (Whenever equipped creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays .)
Equip (: Attach to target creature you control. Equip only as a sorcery.)