Stats
The whip needs 70 Attack and gives +82 slash and +82 strength at a 4-tick speed. It does not degrade, which is why it stays popular for long Slayer trips. Its special, Energy Drain, costs 50% energy and gives 25% more accuracy against slash defence.
There is no aggressive style. Lash shares xp between Attack, Strength and Defence, so a whip cannot train Strength on its own. Many players keep a dragon scimitar for that.
Where whips come from
Abyssal demons drop the whip at 1/512 and need 85 Slayer. Their superior, the greater abyssal demon, gets three rolls at that rate. The Unsired, offered at the Abyssal Sire, also has a good chance of giving one. Demons are a common high-level task, so plenty of whips reach the GE.
The tentacle upgrade
Combine a whip with a kraken tentacle from the Kraken to make an abyssal tentacle: 75 Attack, +8 more slash and +4 more strength, about one extra max hit. The whip is used up for good. The tentacle runs out after 10,000 charges and you get the kraken tentacle back, never the whip.
What moves the price
Supply is steady from Slayer. Demand comes from new members reaching 70 Attack and from tentacle crafting, which removes whips permanently. High alchemy gives 72,000 coins, the floor the price can never fall far below. At higher levels the zombie axe beats the whip against slash-weak and crush-weak targets, and the Ghrazi rapier and Blade of Saeldor replace it at the top. The Attack training guide shows when each switch is worth it.