Dire Undercurrents

Whenever a blue creature you control enters, you may have target player draw a card.
Whenever a black creature you control enters, you may have target player discard a card.

Secret Lair Drop

Shadowmoor

Whenever a blue creature comes into play under your control, you may have target player draw a card.
Whenever a black creature comes into play under your control, you may have target player discard a card.

An object that’s both of the listed colors will cause both abilities to trigger. You can put them on the stack in either order.