Kelvin, arctic Explorer

At the start of each combat phase you may select
up to 3 creatures and opponent controls and 3 creatures you control including Kelvin. Your 3 creatures have +0/2 for that combat phase, and blockers may only be chosen for the 3 attacking creatures out of the 3 defending creatures that were selected.
Creatures selected may be blocked, and it only takes one blocker to fully block them.