At the beginning of combat on your turn, target creature you control gets +1/+0 and gains haste until end of turn.

Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

At the beginning of combat on your turn, target creature you control gets +2/+0 and gains trample and haste until end of turn.

Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)