Benevolent Hydra enters with X +1/+1 counters on it. If one or more +1/+1 counters would be put on another creature you control, that many plus one +1/+1 counters are put on it instead. {T}, Remove a +1/+1 counter from Benevolent Hydra: Put a +1/+1 counter on another target creature you control.

Trample Domain — Whenever this creature deals combat damage to a player, put X +1/+1 counters on target creature you control, where X is the number of basic land types among lands you control.

This creature enters with X +1/+1 counters on it. This creature can't be blocked by more than one creature. Whenever this creature is dealt damage, put that many +1/+1 counters on it. (It must survive the damage to get the counters.)