Abilities

[RDJDenley]

Vectis Siencers can tap 1BB to gain death touch until the end of the turn.

Does this mean I can use his ability when I declare him as a blocker or in my main phase the turn before?

So many questions haha

[Gorzo]

 {Vectis Silencers}

This is what's known as an "activated ability" in magic. You can spot an activated ability on a card because they always appear in the same form - [cost]: [effect]. They will always have a cost (in this case, one black mana and two mana of any color), a colon ( : ) and then an effect (in this case, granting the creature Deathtouch until end of turn).

Activated abilities may be used at any time you have priority, or in other terms, any time you may play an instant. An activated ability is NOT a spell (cannot be targeted by {Cancel} for example but CAN be targeted by {Stifle}) but activated abilities use the stack the same way that spells do.

In short, yes, you sure can use this ability in response to blockers being declared for instant-speed Deathtouch!

RESOLVED

[DylanW18]

This ability can be activated at any time. The only time a creatures ability couldn't be activated is if it said "Activate this only at sorcery speed" or something of that nature. Example {Birthing Pod}'s final line