Hotheaded Giant

Haste
Hotheaded Giant enters with two -1/-1 counters on it unless you've cast another red spell this turn.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Experimental Synthesizer

When Experimental Synthesizer enters or leaves the battlefield, exile the top card of your library. Until end of turn, you may play that card.
{2}{R}, Sacrifice Experimental Synthesizer: Create a 2/2 white Samurai creature token with vigilance. Activate only as a sorcery.

Chain Lightning

Chain Lightning deals 3 damage to any target. Then that player or that permanent's controller may pay {R}{R}. If the player does, they may copy this spell and may choose a new target for that copy.

Mountain

Giant's Ire

Giant's Ire deals 4 damage to target player or planeswalker. If you control a Giant, draw a card.

Stinkdrinker Daredevil

Giant spells you cast cost {2} less to cast.

Crush Underfoot

Choose a Giant creature you control. It deals damage equal to its power to target creature.

Blind-Spot Giant

Blind-Spot Giant can't attack or block unless you control another Giant.

Squash

This spell costs {3} less to cast if you control a Giant.
Squash deals 6 damage to target creature or planeswalker.