Kolodin, Triumph Caster

Mounts and Vehicles you control have haste.
Whenever a Mount you control enters, it becomes saddled until end of turn.
Whenever a Vehicle you control enters, it becomes an artifact creature until end of turn.

Giant Ox

This creature crews Vehicles using its toughness rather than its power.

Have

Bulwark Ox

Whenever this creature attacks while saddled, put a +1/+1 counter on target creature.
Sacrifice this creature: Creatures you control with counters on them gain hexproof and indestructible until end of turn.
Saddle 1 (Tap any number of other creatures you control with total power 1 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery.)